Patent Description:
Field tests provide some information on factors influencing spray drift. However, field tests are limited by weather conditions that may not be controlled and often vary during a test. Due to non-controlled environment, assessing the influence of some variables on spray drift is difficult. Laboratory tests are used to evaluate drift associated with spray deposits discharged from spray tips at various wind velocities in wind tunnels. However, wind tunnels are generally costly and may expose the tester to the agricultural spray, which may have negative health effects on the tester.

The US EPA will soon implement a new Drift Reduction Technology (DRT) program which would allow producers and other applicators to reduce the size of buffer zones required on some herbicide labels. DRT will need to be certified through spray particle analysis or field trials proving a reduction in fine droplets subject to off-target drift. More frequent use of wind tunnels may be required for certification. <CIT> ·discloses a wind tunnel device defining a cyclical tunnel to receive continuous airflow. Airflow is delivered through the tunnel to a testing region that includes a first portion carrying an arm including a spray tip configured to spray particulates in the testing region at an angle, and a second portion including an enlarged cutout region configured to receive the angled sprayed particulates. As airflow carries the angled spray particulates into the second portion, the enlarged cutout region enables the spray particulates to pass through and exit the second portion of the testing region. Analysis in the second region may be conducted through transparent walls free of openings to minimize exposure of the spray particulates to the exterior of the device. A scrubber is adapted to extract spray mist from the airflow as the airflow exits the testing region and is re-circulated through the cyclical tunnel. <CIT> ·discloses a wind tunnel and method of use thereof. The wind tunnel has an airflow system which is capable of delivering air vertically down through, and optionally horizontally across, a spray chamber having transparent sidewalls, wherein spray particulates produced in the spray chamber can be analyzed through the transparent sidewalls, preferably by use of a laser. The dimensions of the spray chamber are preferably greater than that of the airflow system. The use of the wind tunnel enables a wider range and more accurate spray particle measurements, especially for an agrochemical composition, to be made in a single test environment. <CIT> ·discloses optical imaging systems and methods investigating and analyzing one or more characteristics of a spray, including spray front velocity, spray sheet length, spray break-up dynamics, drift potential, and drop-size distribution. Optical imaging systems disclosed herein include an image acquisition device, one or more illumination source, a processor for processing and analyzing image data, a background, and a spray system that includes at least a nozzle. The image acquisition device and illumination sources are positioned on the same side of the spray. The processor has a first algorithm to generate a feedback correction factor and a second algorithm to identify droplets and develop a drop-size distribution for the spray. Optical imaging methods for determining spray characteristics are also disclosed and generally include the steps of providing an imaging system, capturing images of the spray with the imaging system, processing the images, and analyzing the images.

The present application provides a wind tunnel and method in accordance with the claims which follow.

The drawings illustrate several embodiments of the present disclosure, wherein identical reference numerals refer to identical or similar elements or features in different views or embodiments in the drawings.

The embodiments disclosed herein relate to wind tunnels including test sections, and methods of using the wind tunnels disclosed herein. In an embodiment, an example test section includes at least one surface defining an at least partially enclosed space. The at least partially enclosed space defines an airflow path for air to flow through. The test section also includes a nozzle disposed in the at least partially enclosed space. The nozzle is configured to spray an agricultural spray. An agricultural spray may be a composition (including additives such as adjuvants) having a beneficial effect when sprayed on an agricultural target from the nozzle. The nozzle is positioned and configured to emit the agricultural spray so at least a portion of the agricultural spray exhibits a non-parallel angle relative to the airflow path defined by the at least partially enclosed space. The non-parallel angle of the agricultural spray may enable the detection of the bag rupture approach to droplet formation, a newly discovered mechanism of droplet formation disclosed herein. The test section also includes a stimulus source (e.g., light source) positioned to illuminate at least a portion of the agricultural spray adjacent to the nozzle. The test section further includes at least one detector positioned to image the portion of the agricultural spray that is adjacent to the nozzle. The stimulus source may illuminate and the detector may detect portions of the agricultural spray that are adjacent to the nozzle since the bag rupture approach to droplet formation occurs in the portion of the agricultural spray that are adjacent to the nozzle.

The test section and the wind tunnels disclosed herein may detect one or more spray characteristics of the agricultural spray before the agricultural spray is used in field tests and subsequently in field application. In an embodiment, the test section and the wind tunnels disclosed herein may detect and/or quantify one or more disadvantageous spray attributes of the agricultural spray. For example, agricultural sprays often produce driftable small droplets exhibiting a diameter of about <NUM> or less ("small droplets"). These small droplets are susceptible to off-target drift which may cause the agricultural spray to be deposited on unintended plant surfaces causing injury or harm to the vegetation. Traditional measures of reducing the quantity of small droplets formed from the agricultural spray, such as by nozzle design or chemical adjuvant additive, often increases the number of ultra-coarse droplets exhibiting a diameter greater than <NUM> ("ultra-coarse droplets"). High rates of ultra-coarse droplets diminish the area coverage of the agricultural spray. The reduced area coverage has been linked to reduced efficacy of the agricultural spray performance and the evolution of chemical-resistance in commonly-treated weed species.

The number of small droplets and/or ultra-coarse droplets may depend on the atomization mechanism that forms the droplets. It was believed that spray sheets formed from flat fan nozzles, the most common nozzle class in agricultural applications, and other types of nozzles were dominated by two atomization mechanisms: the wave instability and perforation approaches of droplet formation. For the wave instability approach, ligament formation may be produced by aerodynamically-induced wave instabilities. These instabilities grow to generate wave fronts within the spray sheet region just downstream of the nozzle. These wave fronts form continuous thick and thin bands. The thin bands eventually collapse, forming ligaments from the thick bands, which collapse into droplets. In the perforation approach, the spray sheet may perforate, generating voids within the spray sheet which grow to form a web-like structure of ligaments. This ligament structure eventually continues to collapse into droplets. Regardless of the atomization mechanism for these spray sheets, a wide geometric spectrum of droplet sizes is produced.

The number of small droplets and/or ultra-coarse droplets were tested in wind tunnels including test sections that differ from the test sections disclosed herein. For example, the previously used test sections included a flat fan nozzle configured to emit the agricultural spray in a spray sheet that extends parallel to air flowing in the previously used test section. The previously used test section also included a light source and a detector that are positioned to illuminate and image a portion of the spray sheet sufficiently spaced from the nozzle that the wave instability and perforation approaches of droplet formation have formed the droplets. This allowed the light source and the detector to detect and quantify the number of small and ultra-coarse droplets formed from the agricultural spray.

However, using agricultural sprays that included polymers (e.g., agricultural sprays including drift reduction adjuvant compositions that, in theory, are configured to minimize the formation of small droplets) in field tests demonstrated that the agricultural sprays, under certain circumstances, formed more small droplets than the same agricultural spray used in the previously used test section. To determine the cause of the greater than expected number of small droplets during field tests, it was recently discovered that a third atomization mechanism may cause the formation of small droplets: the bag rupture approach to droplet formation. The bag rupture approach to droplet formation is caused by a polymer in the spray tank composition. The bag rupture approach is caused by the formation of a continuous liquid phase in the spray sheet near the nozzle. A portion of the continuous liquid phase of the spray sheet is subjected to hydrodynamic forces associated with the fluid discharge and certain surrounding environmental forces (e.g., aerodynamic forces of the environment) which may cause a formation of a thin membraned semi-spherical protrusion, which is referred to as a "bag" herein. Upon rupture, the thinnest portion of the bag membrane atomizes thereby generating a large number of small droplets ejected in a direction generally perpendicular to the spray sheet. These small droplets are susceptible to drift because the small droplets trajectories are aligned with the environmental wind conditions (i.e., not oriented toward the target location) and the small droplets are dominated by environmental forces (e.g., aerodynamic forces) and not by gravitational forces. The remainder of the bag membrane further collapses into various ligament geometries and contrails. In an example, circumstances that may cause the bag rupture approach includes air movement around the continuous liquid phase of the spray sheet induced by atmospheric wind conditions and/or travel speed of an applicator of the agricultural spray (i.e., the speed that a tractor or other device that includes the nozzle moves relative to a ground surface), or a spray sheet discharging in a direction perpendicular to the surrounding air flow.

The test section and the wind tunnels disclosed herein can detect the bag rupture approach to droplet formation for at least several reasons. The nozzle emits the agricultural spray in a spray sheet so at least a portion of the spray sheet exhibits a non-parallel angle relative to the airflow path of the enclosed space and, thus, the spray sheet is oriented at a non-parallel angle relative to the air flowing through the test section. The non-parallel angle allows the test section to replicate cross-wind conditions that the agricultural sprays are commonly subjected to during field tests that cause the bag rupture approach to droplet formation. Further, the stimulus source illuminates and the detector images portions of the spray sheet that are proximate to the nozzle. This allows the detector to detect the bag rupture approach to droplet formation since the spray sheet only forms the bag near the nozzle.

<FIG> are cross-section and top plan views, respectively, of a test section <NUM>, according to an embodiment. The test section <NUM> includes at least one surface defining an enclosed space <NUM>. The test section <NUM> includes at least one nozzle <NUM> disposed in the enclosed space <NUM> configured to dispense an agricultural spray <NUM> therefrom. The test section <NUM> also includes at least one stimulus source <NUM> configured to emit a stimulus <NUM> that illuminate at least a portion <NUM> (shown in phantom lines) of the agricultural spray <NUM> that is proximate to the nozzle <NUM>. The test section <NUM> also includes a detector <NUM> configured to image at least the portion <NUM> of the agricultural spray <NUM> that is proximate to the nozzle <NUM>. In the illustrated embodiment, the stimulus source <NUM> and the detector <NUM> are positioned outside of the enclosed space <NUM>. The at least one surface includes at least one transparent section <NUM> which allows the stimulus <NUM> to enter the enclosed space <NUM> and the detector <NUM> to image the portion <NUM> of the agricultural spray <NUM>. However, it is noted that, in some embodiments, at least one of the stimulus source <NUM> or the detector <NUM> may be disposed in the at least one surface and/or disposed in the enclosed space <NUM>.

In an embodiment, the at least one surface (e.g., at least one wall) that defines that enclosed space <NUM> may include a plurality of surfaces. In an example, as illustrated, the at least one surface may include a top surface <NUM>, an opposing bottom surface <NUM>, and two lateral surfaces <NUM> extending between the top surface <NUM> and the bottom surface <NUM>. Each of the top surface <NUM>, the bottom surface <NUM>, and the two lateral surfaces <NUM> may be substantially planar. Forming the top surface <NUM>, the bottom surface <NUM>, and the two lateral surfaces <NUM> to be substantially planar may facilitate construction of the test section <NUM> since such components are readily available and, optionally, may be connected together using commonly available mechanical attachment devices (e.g., L-shapes brackets). Further, as discussed in more detail below, forming the top surface <NUM>, the bottom surface <NUM>, and the two lateral surfaces <NUM> to be substantially planar may allow the enclosed space <NUM> to exhibit a substantially continuous cross-sectional shape which may improve the uniformity of air <NUM> (shown schematically with an arrow <FIG>) flowing through the enclosed space <NUM>. However, it is noted that at least one of the top surface <NUM>, the bottom surface <NUM>, or the two lateral surfaces <NUM> may not be substantially planar. For example, at least one of the top surface <NUM>, the bottom surface <NUM>, or the two lateral surfaces <NUM> may be curved (e.g., convexly or concavely curved) and/or, as will be discussed in more detail below, may include one or more recesses formed therein. Further, it is understood that the plurality of surfaces may include less than or more than four surfaces, depending on the application, and that these surfaces may exhibit the same characteristics discussed regarding the top surface <NUM>, the bottom surface <NUM>, and the two lateral surfaces <NUM>. For example, the at least one surface that defines the enclosed space may include a single surface (e.g. continuous) formed from a pipe.

The cross-sectional shape of the enclosed space <NUM> may depend on the number of surfaces that define the enclosed space <NUM>. For example, as illustrated, the enclosed space <NUM> exhibits a generally square or rectangular shape because the enclosed spaced <NUM> is defined by four surfaces (e.g., the top surface <NUM>, the bottom surface <NUM>, and the two lateral surfaces <NUM>). Forming the enclosed space <NUM> to exhibit the generally square or rectangular shape facilitates operation of the test section <NUM>. For example, unlike some other shapes, the generally square or rectangular shape of the enclosed space <NUM> causes the bottom surface <NUM> and the two lateral surfaces <NUM> to be sufficiently spaced from the nozzle <NUM> these surfaces are unlikely to interact with the agricultural spray <NUM> until all the droplets have been formed. Further, the generally square or rectangular shape of the enclosed space <NUM> allows the two lateral surfaces <NUM> to be generally parallel to a direction that the nozzle <NUM> emits the agricultural spray <NUM> (e.g., at least one of generally parallel to gravity or perpendicular to a ground surface) which may allow the stimulus <NUM> entering and/or leaving the enclosed space <NUM> through the transparent sections <NUM> to be perpendicular to the transparent sections <NUM>. The perpendicular angle between the stimulus <NUM> and the transparent sections <NUM> may reduce any effect caused by refracting the stimulus <NUM>. However, it is noted that enclosed space <NUM> may exhibit a generally non-square or non-rectangular shape, depending on the application, without limitation. Further, it is noted that the stimulus <NUM> entering and/or exiting the enclosed space <NUM> may exhibit a non-perpendicular angle relative to the transparent sections <NUM>.

In an embodiment, the enclosed space <NUM> may exhibit a cross-sectional shape and cross-section dimension(s) that do not vary along a length of the enclosed space <NUM>. Not varying the cross-sectional shape and the cross-section dimension(s) of the enclosed space <NUM> may increase the uniformity of the air <NUM> flowing through the enclosed space <NUM> (e.g., reduce turbulent air flow). The increased uniformity of the air <NUM> flowing through the enclosed space <NUM> may improve the repeatability of any test performed in the test section <NUM>. However, in some embodiments, the enclosed space <NUM> may exhibit a cross-section shape and/or cross-section dimension(s) that vary along at least a portion of the length of the enclosed space <NUM>. In an example, as will be discussed below, the cross-sectional shape of the enclosed space <NUM> may vary to include recesses (e.g., recess <NUM>). In an example, the cross-sectional dimension(s) of the enclosed space <NUM> may vary to modify the speed of the air <NUM> flowing through the test section <NUM>. For instance, decreasing a cross-sectional dimension may increase the speed of the air <NUM> while increasing a cross-sectional dimension may decrease the speed of the air <NUM>.

In an embodiment, as illustrated, the enclosed space <NUM> may be completely enclosed. Completely enclosing the enclosed space <NUM> may increase the uniformity of the air <NUM> flowing through the enclosed space <NUM>. However, the enclosed space <NUM> may only be partially enclosed. In an example, the at least one surface that defines the enclosed space <NUM> may include one or more unoccupied openings that may allow devices to be inserted into the enclosed space <NUM> during operation or otherwise provide access to the enclosed space <NUM> during operation.

As previously discussed, at least one of the surface that define the enclosed space <NUM> may define at least one recess therein. In an embodiment, as illustrated, the bottom surface <NUM> defines a recess <NUM> therein. The recess <NUM> may be configured to receive at least a portion of the agricultural spray <NUM> dispensed into the enclosed space <NUM> and may channel the agricultural spray <NUM> towards an outlet (not shown) thereby removing the agricultural spray <NUM> from the enclosed space <NUM>. The bottom surface <NUM> may include a slightly tapered topography to channel the agricultural spray <NUM> towards the recess <NUM>. In an embodiment, the at least one surface may define one or more recesses to accommodate a spray angle of the agricultural spray. For example, the two lateral surfaces <NUM> may define one or more recesses near an intersection of the two lateral surfaces <NUM> and the bottom surface <NUM> to decrease the likelihood that the two lateral surfaces <NUM> contact the agricultural spray <NUM>.

As previously discussed, the at least one surface that defines the enclosed space <NUM> may include at least one transparent section <NUM>. The transparent section <NUM> allows at least one individual or device located outside of the enclosed space <NUM> to view the enclosed space <NUM> during operation. In an embodiment, as illustrated, both the stimulus source <NUM> and the detector <NUM> are disposed outside of the enclosed space <NUM>. In such an embodiment, the at least one transparent section <NUM> may include a first transparent section formed in one of the two lateral surfaces <NUM> and a second transparent section formed in the other of the two lateral surfaces <NUM>. The stimulus source <NUM> may be positioned relative to the first transparent section so the stimulus <NUM> enters the enclosed space <NUM> through the first transparent section. The stimulus <NUM> that enters the enclosed space <NUM> may illuminate at least the portion <NUM> of the agricultural spray <NUM> that is adjacent to the nozzle <NUM>. The detector <NUM> may be positioned relative to the second transparent section so the detector <NUM> images at least the portion <NUM> of the agricultural spray <NUM> that is adjacent to the nozzle <NUM> through the second transparent section. The illustrated configuration is beneficial since the stimulus <NUM> passes through the agricultural spray <NUM> which may increase the resolution of the image detected by the detector <NUM>. However, it is noted that the transparent section <NUM> and the position of the stimulus source <NUM> and the detector <NUM> may differ from the illustrated embodiment. For example, the transparent section <NUM> may only include a single transparent section (e.g., the stimulus source <NUM> is positioned to emit the stimulus <NUM> through the single transparent section and the detector <NUM> images the enclosed space <NUM> through the single transparent section), the transparent section <NUM> includes three or more transparent sections, or at least one of the stimulus source <NUM> or the detector <NUM> are disposed in the enclosed space <NUM>.

As previously discussed, the enclosed space <NUM> defines an airflow path for air <NUM> (schematically illustrated with an arrow in <FIG>) to flow during operation. Generally, during operation, the average direction that the air <NUM> flows through the enclosed space <NUM> is parallel to the airflow path of the enclosed space <NUM>. As such, as used herein, the average direction that the air <NUM> flows through the enclosed space <NUM> and the airflow path of the enclosed space <NUM> may be used interchangeably without limitation. However, it is noted that the average direction that the air <NUM> flows through the enclosed space <NUM> may vary slightly (e.g., less than <NUM>° or less than <NUM>°) from the airflow path due to turbulent air flow, recesses in the at least one surface, etc..

As previously discussed, the at least one nozzle <NUM> may be disposed in the enclosed space <NUM> and is configured to dispense the agricultural spray <NUM> into the enclosed space <NUM>. In an embodiment, the nozzle <NUM> is positioned and configured to dispense the agricultural spray <NUM> in a direction at least one of parallel to gravity or perpendicular to ground (e.g., perpendicular to at least a portion of the bottom surface <NUM>). Dispensing the agricultural spray <NUM> in a direction that is parallel to gravity or perpendicular to the ground mimics conventional methods of dispensing agricultural sprays on crops and is conducive to detecting the formation of bags in the spray sheet of the agricultural spray <NUM>. However, the nozzle <NUM> may be positioned and configured to dispense the agricultural spray <NUM> in a direction not at least one of parallel to gravity or perpendicular to the ground.

According to the invention, the nozzle <NUM> is a flat fan nozzle since flat fan nozzles are commonly used to dispense agricultural sprays and the spray fan formed from the flat fan nozzle is conducive to forming droplets via the bag rupture approach. In an embodiment, the nozzle <NUM> may include a hollow cone nozzle since the spray fan formed from the hollow cone nozzle is conducive to forming droplets via the bag rupture approach. In an embodiment, the nozzle <NUM> may include nozzles manufactured by TeeJet (TTI <NUM> nozzle, XR11002-XR TeeJet Extended Range Flat Spray Tip, AIXR11004-AIXR TeeJet Spray Tip), Hypro, Greenleaf, Wilger, Lechler, including nozzle models such as AIXR, AI, TT, UCD and so on. It is noted that, while these nozzles are configured to dispense agricultural sprays, it is noted that these nozzles may also dispense other fluids (e.g., the test section <NUM> may test non-agricultural spray liquids).

In an embodiment, the flow rates of the agricultural spray <NUM> through the nozzle <NUM> may be about <NUM>,<NUM> liters per min (<NUM>/min) (<NUM> gallon per minute ("gpm")) to about <NUM>,<NUM><NUM>/min (<NUM> gpm), such as about <NUM>,<NUM><NUM>/min (<NUM> gpm) to about <NUM>,<NUM><NUM>/ min (<NUM> gpm), or about <NUM>,<NUM><NUM>/min (<NUM> gpm) to about <NUM>,<NUM><NUM>/min (<NUM> gpm). In an embodiment, the nozzle <NUM> may emit the agricultural spray <NUM> at a spray angle of about <NUM>° to about <NUM>°, up to about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>° or about <NUM>°. In an embodiment, the nozzle <NUM> may be operated at up to <NUM>,<NUM> bar (<NUM> psi) fluid pressure, or up to about <NUM>,<NUM> bar (<NUM> psi), up to about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi) to about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi) to about <NUM> psi fluid pressure, or about <NUM> psi, about <NUM> psi, about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi), about <NUM>,<NUM> bar (<NUM> psi) fluid pressure, or any integer range of the aforementioned pressure levels (e.g., about <NUM>,<NUM> bar (<NUM> psi) to about <NUM>,<NUM> bar (<NUM> psi)).

Referring to <FIG>, the nozzle <NUM> is positioned and configured to dispense the agricultural spray <NUM> so at least a portion of a spray sheet of the agricultural spray <NUM> exhibits an spray orientation angle θ relative to the direction that the air <NUM> flows through the enclosed space <NUM>. In a top plan view, the spray orientation angle θ is the angle measured clockwise from the spray sheet of the agricultural spray <NUM> to the average direction that the air <NUM> intersects the spray sheet. Additionally, the nozzle <NUM> is positioned and configured to dispense the agricultural spray <NUM> so at least a portion of a spray sheet of the agricultural spray <NUM> exhibits the spray orientation angle θ relative to the airflow path of the enclosed space <NUM> since, as previously discussed, the direction that the air <NUM> flows through the enclosed space <NUM> and the airflow path of the enclosed space <NUM> are substantially the same. In an example, when the nozzle <NUM> is a flat fan nozzle, all of the spray sheet of the agricultural spray exhibits the spray orientation angle θ relative to the direction that the air <NUM> flows through the enclosed space <NUM>. In an example, when the nozzle <NUM> is a hollow cone nozzle or another nozzle that forms a curved spray sheet, only a portion of the spray sheet of the agricultural spray <NUM> may exhibit the spray orientation angle θ.

Unlike conventional wind tunnels, the nozzle <NUM> is positioned and configured so the spray orientation angle θ is non-parallel to the direction that the air <NUM> flows through the enclosed space <NUM>. Selecting the spray orientation angle θ to be non-parallel to the direction that the air <NUM> flows through the enclosed space <NUM> allows the spray sheet of the agricultural spray <NUM> to be exposed to simulated crosswinds. It is the simulated crosswinds that may cause the spray sheet of the agricultural spray <NUM> to exhibit the bag rupture approach to droplet formation. For example, the spray orientation angle θ may be selected to be about <NUM>° to about <NUM>°. However, the spray orientation angle θ is more preferably selected to be about <NUM>° to about <NUM>° and, even more preferably, about <NUM>° to about <NUM>° or about <NUM>° to about <NUM>° since the spray sheet of the agricultural spray <NUM> is more likely to exhibit the bag rupture approach to droplet formation the closer the spray orientation angle θ is to <NUM>°. In an example, the spray orientation angle θ may be selected to be about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°.

In an embodiment, the spray orientation angle θ may be selected so the spray sheet of the agricultural spray <NUM> exhibits a selected orientation relative to the detector <NUM>. In an example, the spray sheet of the agricultural spray <NUM> may be oriented so the image plane detected by the detector <NUM> is generally parallel to the spray sheet which may allow the detector <NUM> to detect the formation and rupture of bags along a width of the spray sheet. In such an example, the spray orientation angle θ may be selected to be generally perpendicular (e.g., about <NUM>° to about <NUM>° or about <NUM>° to about <NUM>°) to the direction that the air <NUM> flows through the enclosed space <NUM> when the detector <NUM> is oriented at a generally perpendicular angle relative to the direction that the air <NUM> flows through the enclosed space <NUM>. In an example, the spray sheet of the agricultural spray <NUM> may be oriented so the image plane detected by the detector <NUM> is generally perpendicular to the spray sheet which may allow the detector <NUM> to detect the edge of the spray sheet and, more particularly, the profile of the bags formed in the spray sheet. In such an example, the spray orientation angle θ may be selected to be nearly parallel (e.g., about <NUM>° to about <NUM>° or about <NUM>° to about <NUM>°) to the direction that the air <NUM> flows through the enclosed space <NUM> when the detector <NUM> is oriented at a generally perpendicular angle relative to the direction that the air <NUM> flows through the enclosed space <NUM>. In an embodiment, the detector <NUM> is moved (e.g., moved manually or with an actuator) instead of or in conjunction with selecting the spray orientation angle θ to obtain a desired image.

In an embodiment, the nozzle <NUM> may be configured to be selectively repositioned (e.g., rotated) to controllably change the spray orientation angle θ. For example, <FIG> illustrates that the spray orientation angle θ is a generally obtuse angle. However, <FIG>, which is a top plan view of the test section <NUM> after the nozzle <NUM> is selectively repositioned, the spray orientation angle θ is about <NUM>°. The nozzle <NUM> may be configured to be selectively repositioned using any suitable method. In an example, the nozzle <NUM> may be configured to be manually repositioned by an individual disposed in the enclosed space <NUM>. In such an example, the nozzle <NUM> may only be repositioned when the test section <NUM> is being used. In an example, the nozzle <NUM> may be coupled to an actuator, such as an electric motor, which is configured to controllably reposition the nozzle <NUM>. In such an example, the nozzle <NUM> may be repositioned during operation of the test section <NUM> (e.g., while the nozzle <NUM> is dispensing the agricultural spray <NUM>) thereby allowing the test section <NUM> to test the agricultural spray <NUM> at multiple spray orientation angles θ in a single test. It is noted that, in some embodiments, the nozzle <NUM> may be moved up and/or down (e.g., either manually or using an actuator).

In an embodiment, the test section <NUM> and/or a wind tunnel that includes the test section <NUM> may include a fluid reservoir (not shown), such as a tank, that is configured to hold the agricultural spray <NUM>. In such an embodiment, the nozzle <NUM> may be fluidly coupled to the fluid reservoir so the nozzle <NUM> may receive and dispense the agricultural spray <NUM>. Examples of the agricultural sprays that may be stored in the fluid reservoir are disclosed in <CIT>, <CIT>, and U. Patent Application entitled "Methods of Using Drift Reduction Adjuvant Compositions". It is noted that, in an embodiment, the fluid reservoir may include liquid that is not an agricultural spray. In such an embodiment, the nozzle <NUM> may receive and dispense the liquid and the test section <NUM> may test liquids that are not agricultural sprays.

The stimulus source <NUM> may include any suitable device that may illuminate the portion <NUM> of the agricultural spray <NUM> in a manner that allows the detector <NUM> to detect the portion <NUM> of the agricultural spray <NUM>. Generally, the stimulus source <NUM> is an electromagnetic source configured to emit visible light. Examples of the stimulus source <NUM> that emit visible light includes a light emitting diode ("LED"), a flash bulb, a halogen light, a mercury light, a xenon lamp, or a laser. However, it is noted that the stimulus source <NUM> may include an electromagnetic source configured to emit non-visible light (e.g., ultraviolet light or infrared light) or another stimulus source (e.g., acoustic source). In an embodiment, the stimulus source <NUM> may include a single stimulus source (as shown) or a plurality of stimulus sources.

In an embodiment, as illustrated, the stimulus source <NUM> is disposed outside of the enclosed space <NUM>. Disposing the stimulus source <NUM> outside of the enclosed space <NUM> may prevent the agricultural spray <NUM> from inadvertently coming in contact with the stimulus source <NUM>. For example, contacting the stimulus source <NUM> with the agricultural spray <NUM> may dirty the stimulus source <NUM> thereby reducing the intensity of the stimulus <NUM> emitted from the stimulus source <NUM> and/or prevent the agricultural spray <NUM> from damaging the electronics of the stimulus source <NUM>. However, as previously discussed, the stimulus source <NUM> may be at least partially disposed in the enclosed space <NUM>.

In an embodiment, the stimulus source <NUM> is a pulsed light source, such as a pulsed laser, a pulsed LED, or a flash bulb. The pulsed light source may discharge a large amount of light (i.e., high intensity) during a short period of time. The large amount of light allows for a high resolution image, especially when the background light levels are low. In an embodiment, the stimulus source <NUM> is a continuous light source, such as an LED light source, a halogen light source, a mercury light source, or a xenon lamp. The continuous light source may be used, for example, when the desired imaging frame rate is too fast for a pulsed light source to recharge.

In an embodiment, the stimulus source <NUM> includes a laser, such as a pulsed laser. In such an embodiment, the stimulus source <NUM> may include at least one of an aspheric lens <NUM>, a positive or negative (concave, convex) spherical lens, a combination of positive and negative concave lenses, or other optical elements which causes the laser beam to diverge. Diverging the laser beam allows the stimulus <NUM> emitted from the stimulus source <NUM> to illuminate the portion <NUM> of the agricultural spray <NUM> instead of just a small dot.

In an embodiment, the stimulus source <NUM> may be configured to move. For example, the stimulus source <NUM> may include or be operably coupled to an actuator that may move the stimulus source <NUM>. For instance, the actuator may change the position of the stimulus source <NUM> relative to the enclosed space <NUM> or change the direction that the stimulus source <NUM> emits the stimulus <NUM>.

In an embodiment, the test section <NUM> may include a diffuser <NUM> disposed between the stimulus source <NUM> and the agricultural spray <NUM>. For example, the diffuser <NUM> may be positioned on the transparent section <NUM> that is positioned between the agricultural spray <NUM> and the stimulus source <NUM>. The diffuser <NUM> may soften the stimulus <NUM> emitted from the stimulus source <NUM> thereby reducing the harsh light and hard shadows detected by the detector <NUM> which may increase the resolution of image detected by the detector <NUM>. The diffuser <NUM> may also cause a single stimulus source to behave like a plurality of stimulus sources that illuminate the agricultural spray <NUM> from many angles thereby increasing the contrast of the detected image. Further, in some embodiments, the diffuser <NUM> may provide a uniform background for the image detected by the detector <NUM> which may increase the contrast of the detected image.

The type of detector <NUM> that is selected to image the portion <NUM> of the agricultural spray <NUM> may depend on the stimulus <NUM> emitted from the stimulus source <NUM>. For example, the detector <NUM> may include a camera or other detector of visible light if the stimulus <NUM> is visible light or may include an ultraviolet or infrared detector if the stimulus <NUM> is ultraviolet light or infrared light, respectively.

In an embodiment, the detector <NUM> may include a high frame rate camera or a low frame rate camera. The low frame rate camera may allow the capture high resolution (>20megapixel) images which allows for the close examination of images (e.g. to identify the presence of bags). The high speed camera may offer the temporal resolution to examine the formation and collapse of a bag membrane but may lack the resolution (<4megapixels) for close study.

In an embodiment, as illustrated, the detector <NUM> is disposed outside of the enclosed space <NUM>. Disposing the detector <NUM> outside of the enclosed space <NUM> may prevent the agricultural spray <NUM> from inadvertently coming in contact with the detector <NUM>. For example, contacting the detector <NUM> with the agricultural spray <NUM> may dirty a lens of detector <NUM> thereby reducing the resolution of the image detected by the detector <NUM> and/or damage the electronics of the detector <NUM>. However, as previously discussed, the detector <NUM> may be at least partially disposed in the enclosed space <NUM>.

In an embodiment, the detector <NUM> may be configured to move. For example, the detector <NUM> may include or be operably coupled to an actuator that may move the detector <NUM>. For instance, the actuator may change the position of the detector <NUM> relative to the enclosed space <NUM> or change the direction that the detector <NUM> faces.

In an embodiment, as illustrated, the test section <NUM> may only include a single detector. In another embodiment, the test section <NUM> may include a plurality of detectors. The plurality of detectors may have different positions so the plurality of detectors image different portions of the agricultural spray <NUM> simultaneously. For example, one of the plurality of detectors may be positioned so the detected image plane is generally parallel to the spray sheet of the agricultural spray <NUM> while another one of the plurality of detectors may be positioned so the detected image plane is generally perpendicular to the spray sheet of the agricultural spray <NUM>. Further, the plurality of detectors may enable the test section <NUM> to both detect the bag rupture approach to droplet formation and quantify the size of the droplets formed from the agricultural spray <NUM>. For instance, at least one of the plurality of detectors may be positioned to image the portion <NUM> of the agricultural spray <NUM> thereby detecting the bag rupture approach to droplet formation while at least one other detector may be positioned to image a portion of the agricultural spray <NUM> sufficiently spaced from the nozzle <NUM> to quantifiably detect the size of the droplets formed from the agricultural spray <NUM>.

As previously discussed, the stimulus source <NUM> is positioned and configured to illuminate at least the portion <NUM> of the agricultural spray <NUM> and the detector <NUM> is positioned and configured to detect at least the portion <NUM> of the agricultural spray <NUM>. In an example, the portion <NUM> of the agricultural spray <NUM> includes a region of the agricultural spray <NUM> initially exiting the nozzle <NUM> that forms the continuous sheet-like portion to define an initial spray pattern, such as a fan-shaped pattern or a cone-shaped pattern. In such an example, the portion <NUM> of the agricultural spray <NUM> may also include additional portions of the agricultural spray <NUM> extending from the initial spray pattern, such as ligament structures formed from the initial spray pattern. In an example, the portion <NUM> of the agricultural spray <NUM> extends from the nozzle <NUM> and includes the area of primary atomization and, optionally, an area of secondary atomization. In such an example, the portion <NUM> allows the atomization of the continuous liquid phase of the agricultural spray <NUM> to be detected (e.g., visually studied). In an example, the portion <NUM> of the agricultural spray <NUM> extends from the nozzle <NUM> until at least the continuous liquid phase of the agricultural spray <NUM> collapses into ligament structures. In such an example, the portion <NUM> may also include regions of the agricultural spray <NUM> after the collapse of the ligament structures. In an example, the portion <NUM> of the agricultural spray <NUM> includes all of the agricultural spray <NUM> except for regions of the agricultural spray <NUM> after substantially full and complete atomization (i.e., substantially no additional droplet formation occurs) is achieved. In an example, the portion <NUM> of the agricultural spray <NUM> extends from the nozzle <NUM> to about <NUM> to about <NUM> times the breakup length of the agricultural spray <NUM>. In an example, a horizontal dimension of the portion <NUM> of the agricultural spray <NUM> is sufficient to adequately capture the entirety of the agricultural spray <NUM> for a given downstream length. In such an example, the horizontal dimension of the portion <NUM> of the agricultural spray <NUM> is a function of the spray angle of the nozzle <NUM>. In an example, a horizontal dimension of the portion <NUM> of the agricultural spray <NUM> does not capture the entirety of the agricultural spray <NUM> for a given downstream length. In such an example, the horizontal dimension of the portion <NUM> may include at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>% of the entirety of the agricultural spray <NUM> for a given downstream length.

<FIG> is a schematic top plan view of a test section <NUM>, according to an embodiment. Except as otherwise disclosed, the test section <NUM> is the same as or substantially similar to any of the test sections disclosed herein. For example, the test section <NUM> includes at least one surface <NUM> defining an enclosed space <NUM>. The test section <NUM> further includes at least one nozzle (not shown) configured to dispense an agricultural spray <NUM> at a desired angle relative to the flow of air <NUM> through the enclosed space <NUM>. Additionally, the test section <NUM> includes a stimulus source <NUM> and a detector <NUM>.

The test section <NUM> includes one or more optical elements configured to facilitate operation of the test section <NUM>. The one or more optical elements may include one or more lenses, one or more apertures, one or more diffusers, or any other suitable optical element.

In an embodiment, the one or more optical elements may include a first lens <NUM> configured to collimate the stimulus <NUM> emitted from the stimulus source <NUM> since the collimating the stimulus <NUM> may improve the resolution of the image detected by the detector <NUM>. Typically, the first lens <NUM> may be spaced from the stimulus source <NUM> though the first lens <NUM> may be adjacent to or integrally formed with the stimulus source <NUM>. The first lens <NUM> is positioned between the stimulus source <NUM> and the agricultural spray <NUM> so the stimulus <NUM> that illuminates the agricultural spray <NUM> is collimated. Generally, the first lens <NUM> is disposed outside of the enclosed space <NUM> thereby preventing the agricultural spray <NUM> from coating and dirtying the first lens <NUM>. However, it is noted that the first lens <NUM> may form the transparent section <NUM> of the at least one surface <NUM> that defines the enclosed space <NUM> or may be disposed in the enclosed space <NUM>.

In an embodiment, the one or more optical elements may include a second lens <NUM> that is a collection lens or a condenser lens that causes the collimated light to converge. In such an embodiment, the one or more optical element may also include an aperture <NUM> (e.g., iris) positioned in series with and closer to the detector <NUM> than the second lens <NUM>. The aperture <NUM> may limit the amount of the stimulus <NUM> that reaches the detector <NUM>. Both the second lens <NUM> and the aperture <NUM> may be positioned between the agricultural spray <NUM> and the detector <NUM>. The second lens <NUM> and the aperture <NUM>, collectively, may improve the resolution of the image detected by the detector <NUM>. Generally, both the second lens <NUM> and the aperture <NUM> are disposed outside of the enclosed space <NUM> thereby preventing the agricultural spray <NUM> from coating and dirtying the second lens <NUM> and the aperture <NUM>. However, it is noted that the second lens <NUM> may form the transparent section <NUM> of the at least one surface <NUM> or at least one of the second lens <NUM> and the aperture <NUM> may be disposed in the enclosed space <NUM>. Further, typically, the second lens <NUM> and the aperture <NUM> are spaced from the detector <NUM> though at least one of the second lens <NUM> or the aperture <NUM> may be adjacent to or integrally formed with the detector <NUM>.

In an embodiment, the one or more optical elements may include a diffuser <NUM>. The diffuser <NUM> may be disposed on the transparent section <NUM> of the surface <NUM>, as shown in <FIG>. However, as illustrated, the diffuser <NUM> may be disposed between the agricultural spray <NUM> and the detector <NUM> thereby softening the light detected by the detector <NUM> and improving the contrast of the image detected by the detector <NUM>. In an example, the diffuser <NUM> may be a diffusion filter attached to the detector <NUM>.

The test section <NUM> may include additional optical elements not illustrated in <FIG>. For example, the test section <NUM> may include at least one lens configured to magnify the portions of the agricultural spray <NUM> detected by the detector <NUM>, one or more aspheric lenses as previous disclosed herein, one or more positive and/or negative spherical lenses, one or more psoitive and/or negative concaved cylindrical lenses, one or more mirrors, one or more optical filters, one or more polarizers, or any other suitable optical element.

As previously discussed, in some embodiments, at least one of the first lens <NUM>, the second lens <NUM>, the aperture <NUM>, the diffuser <NUM>, or the one or more additional optical elements of the test section <NUM> may be spaced from the enclosed space <NUM>. The position of the first lens <NUM>, the second lens <NUM>, the aperture <NUM>, the diffuser <NUM>, or the one or more additional optical elements, relative to the enclosed space <NUM>, may depend on the position of the stimulus source <NUM> and the detector <NUM> relative to the enclosed space <NUM>. For example, the stimulus source <NUM> may be positioned on a first lateral area that is spaced from the enclosed space <NUM> and the detector <NUM> may be positioned on second lateral area that is spaced from the enclosed space <NUM>. The second lateral side may be on an opposing side of the enclosed space <NUM> than the first lateral area. In such an embodiment, the first lens <NUM> may be positioned on the first lateral area between the stimulus source <NUM> and the enclosed space <NUM> and the first lens <NUM> may be discrete from the stimulus source <NUM>. As such, the stimulus <NUM> emitted from the stimulus source <NUM> passes through the first lens <NUM> before the stimulus <NUM> illuminates the agricultural spray <NUM>. Further, the second lens <NUM> and the aperture <NUM> may be positioned in the second lateral area between the enclosed space <NUM> and the detector <NUM> which may improve a resolution of any image that is detected by the detector <NUM>. The second lens <NUM> and the aperture <NUM> may be discrete from the detector <NUM>. As previously discussed, the diffuser <NUM> may be positioned on either the first or second lateral area of the test section <NUM>, depending on the embodiment, and also may be discrete from the stimulus source <NUM> and the detector <NUM>.

<FIG> is a schematic top plan view of a test section <NUM>, according to an embodiment. Except as otherwise disclosed herein, the test section <NUM> is the same as or substantially similar to any of the test sections disclosed herein. For example, the test section <NUM> includes at least one surface <NUM> defining an enclosed space <NUM>. The test section <NUM> further includes at least one nozzle (not shown) configured to dispense an agricultural spray <NUM> at a desired angle relative to the flow of air <NUM> through the enclosed space <NUM>. Additionally, the test section <NUM> includes a stimulus source <NUM> and a detector <NUM>.

The stimulus source <NUM> is configured to emit a collimated stimulus <NUM> which may simplify the test section <NUM> relative to the other test sections disclosed herein. For example, the collimated stimulus <NUM> may eliminate the need for a lens to collimate the stimulus <NUM> (e.g., first lens <NUM> of <FIG>). Further, the collimated stimulus <NUM> may eliminate the need for a diffuser (e.g., diffuser <NUM> or <NUM> of <FIG>) so long as nothing causes significant divergence or convergence of the collimated stimulus <NUM>.

The test sections disclosed herein may be used in any suitable wind tunnel. <FIG> is a schematic top plan view of an example wind tunnel <NUM>, according to an embodiment. The wind tunnel <NUM> includes a test section <NUM>. The test section <NUM> may include any of the test sections disclosed herein. For example, the test section <NUM> may include at least one surface <NUM> defining an enclosed space <NUM>. The test section <NUM> further includes at least one nozzle (not shown) configured to dispense an agricultural spray <NUM> into the enclosed space <NUM>. Additionally, the test section <NUM> includes a stimulus source <NUM> and a detector <NUM>.

The wind tunnel <NUM> further includes a blower <NUM> positioned upstream from the test section <NUM>. The blower <NUM> may include any suitable device for pushing the air <NUM> through the test section <NUM>. The blower <NUM> may be configured to flow the air <NUM> through the enclosed space <NUM> at a selected speed. In an embodiment, the selected speed may be less than about <NUM>,<NUM> kilometres per hour (Km/h) (<NUM> miles per hour "mph"), such as in ranges of about <NUM>/h (<NUM> mph) about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/ h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), about <NUM>,<NUM>/h (<NUM> mph) to about <NUM>,<NUM>/h (<NUM> mph), or combinations thereof. Air speeds that are less than about <NUM> mph may simulate wind conditions that the agricultural spray <NUM> is exposed to when dispensed from a ground applicator, such as a tractor, truck, an individual carrying the nozzle, etc. However, the blower <NUM> may be configured to flow the air <NUM> through the enclosed space <NUM> at speeds greater than <NUM>,<NUM>/h (<NUM> mph), such as greater than <NUM>,<NUM>/h (<NUM> mph), greater than <NUM>,<NUM>/h (<NUM> mph), or greater than <NUM>,<NUM>/h (<NUM> mph) Such high air speeds may simulate wind conditions that the agricultural spray <NUM> is exposed to when dispensed from an air applicator, such as a helicopter or an airplane.

The wind tunnel <NUM> may also include a spray particle scrubber <NUM> positioned downstream from the test section <NUM>. The spray particles scrubber <NUM> may be configured to collect droplets from the wind tunnel <NUM> that reach the spray particle scrubber <NUM> (e.g., spray particles not collected by the recess <NUM>). The spray particle scrubber <NUM> may prevent the spray droplets from continuing down the wind tunnel <NUM>. With the spray particle scrubber <NUM>, the air <NUM> may be reused and provided to the blower <NUM> or the air <NUM> may be emitted into the environment. In an embodiment, the spray particle scrubber <NUM> may be configured as a mist extractor. In an embodiment, the spray particle scrubber <NUM> may be <NUM>% effective at removing particles greater than <NUM> diameter. For example, the spray particle scrubber <NUM> may use angled channels to change the flow path of the particles, allowing them to settle out and run down the channels into a fluid collector (e.g., the recess <NUM>).

In an embodiment, the wind tunnel <NUM> may include at least one of a first tunnel <NUM> or a second tunnel <NUM>. The wind tunnel <NUM> may include the first tunnel <NUM> when the blower <NUM> is spaced from the test section <NUM> and the second tunnel <NUM> when the spray particle scrubber <NUM> is spaced from the test section <NUM>. The first tunnel <NUM> and the second tunnel <NUM> may couple the blower <NUM> and the spray particle scrubber <NUM> to the test section <NUM> so air may flow from the blower <NUM> to the test section <NUM> and from the test section <NUM> to the spray particle scrubber <NUM>. The first and/or second tunnels <NUM>, <NUM> may form a straight airflow path or may be at least partially curved.

In an embodiment, at least one of the first or second tunnel <NUM>, <NUM> may exhibit a cross-sectional shape and cross-section dimension(s) that do not vary along a length thereof. Not varying the cross-sectional shape and the cross-section dimension(s) of at least one of the first or second tunnel <NUM>, <NUM> may increase the uniformity of the air <NUM> flowing through the enclosed space <NUM> (e.g., reduce turbulent air flow). However, in some embodiments, at least one of the first or second tunnel <NUM>, <NUM> may exhibit a cross-section shape and/or cross-section dimension(s) that vary along at least a portion of the length thereof. For example, the cross-sectional dimension(s) of at least one of the first or second tunnel <NUM>, <NUM> may vary to modify the speed of the air <NUM> flowing therein (e.g., decreasing a cross-sectional dimension may increase the speed of the air <NUM> while increasing a cross-sectional dimension may decrease the speed of the air <NUM>).

In an embodiment, the wind tunnel <NUM> may include a computer <NUM>. The computer <NUM> may include a processor, a memory and a network connection. The computer <NUM> may be communicatively coupled to one or more components of the wind tunnel <NUM>. For example, the computer <NUM> may be communicably coupled to at least one of the stimulus source <NUM>, the detector <NUM>, the blower <NUM>, the spray particle scrubber <NUM>, the nozzle (not shown), or another component of the wind tunnel. Using the computer <NUM>, an operator may adjust the angle of the agricultural spray <NUM> relative to the direction of the air <NUM> flowing through the enclosed space <NUM> (e.g., change the angle of the agricultural spray <NUM> relative to the airflow path of the enclosed space <NUM>), cause the stimulus source <NUM> to emit the stimulus <NUM>, image the agricultural spray <NUM>, flow the air <NUM> through the enclosed space <NUM>, or another operation of the wind tunnel <NUM>.

It is noted that the wind tunnel <NUM> is merely an example of a wind tunnel that may include any of the test sections disclosed herein. Further it is noted that the test sections disclosed herein may be used with any suitable wind tunnel without limitation. For instance, further examples of wind tunnels that may include any of the test sections disclosed herein are disclosed in <CIT>, <CIT> filed on November <NUM>, <NUM>, and ANSI/ASABE S592. <NUM> published in the American Society of Agricultural and Biological Engineers.

<FIG> is a flow chart of an example method <NUM> of using a wind tunnel including any of the test sections disclosed herein, according to an embodiment. The method <NUM> may include one or more operations, functions, or actions as illustrated by one or more blocks <NUM>, <NUM>, <NUM>, or <NUM>. For example, the method <NUM> may begin with block <NUM>, which recites "flowing air along an airflow path of an at least partially enclosed space. " Block <NUM> may be followed by block <NUM>, which recites "emitting an agricultural spray from a nozzle such that at least a portion of the agricultural spray exhibits a non-parallel angle relative to the air flowing along the airflow path. " Block <NUM> may be followed by block <NUM>, which recites "emitting a stimulus from at least one stimulus source to illuminate at least a portion of the agricultural spray that is adjacent to the nozzle. " Block <NUM> may be followed by block <NUM>, which recites "imaging at least the portion of the agricultural spray that is adjacent to the nozzle with at least one detector.

The blocks included in the described the example method <NUM> are for illustration purposes. In an example, the blocks may be performed in a different order, eliminated, divided into additional blocks, modified, supplemented with other blocks, or combined into fewer blocks. In an example, the method <NUM> may include additional unrecited blocks, such as at least partially controlling one or more components of the wind tunnel with a computer.

Block <NUM> includes "flowing air along an airflow path of an at least partially enclosed space. " For example, block <NUM> may include activating a blower of the wind tunnel so air flows through the test section. In an embodiment, block <NUM> may include flowing the air through a tunnel extending between the blower and the test section. It is noted that block <NUM> may include controllably selecting and/or changing the speed of the air flowing along the airflow path.

Block <NUM> includes "emitting an agricultural spray from a nozzle such that at least a portion of the agricultural spray exhibits a non-parallel angle relative to the air flowing along the airflow path. " In other words, block <NUM> includes emitting the agricultural spray from the nozzle so at least a portion of the agricultural spray exhibits a non-parallel angle relative to the airflow path of the enclosed space. Block <NUM> may be performed at least one of before, during, or after block <NUM>. For example, if block <NUM> is performed during block <NUM>, block <NUM> may include forming droplets via the bag rupture approach to droplet formation.

Block <NUM> may include controllably selecting and/or adjusting the non-parallel angle between at least a portion of the agricultural spray and the air flowing along the airflow path. For example, block <NUM> may include manually changing the non-parallel angle or may include changing the angle using an actuator coupled to the nozzle.

Block <NUM> includes "emitting a stimulus from at least one stimulus source to illuminate at least a portion of the agricultural spray that is adjacent to the nozzle. " In an example, block <NUM> may include emitting visible light or any of the other stimuli disclosed herein towards at least the portion of the agricultural spray that is adjacent to the nozzle. In an example, block <NUM> may include emitting the stimulus through a transparent section of the at least one surface that defines the enclosed space when the stimulus source is positioned outside of the enclosed space. In an example, block <NUM> may include adjusting (e.g., focusing, collimating, magnifying, diffusing, etc.) the stimulus using one or more optical elements. In an example, block <NUM> may include moving the stimulus source manually or using an actuator. In an example, block <NUM> may be performed at least one of before, during, or after at least one of blocks <NUM> or <NUM>.

Block <NUM> includes "imaging at least the portion of the agricultural spray that is adjacent to the nozzle with at least one detector. " In an example, block <NUM> includes imaging at least a portion of the agricultural spray that is adjacent to the nozzle through at least one transparent section of the at least one surface that defines the enclosed space. In an example, block <NUM> may include adjusting (e.g., focusing, magnifying, diffusing, etc.) the image detected by the detector using one or more optical elements. In an example, block <NUM> may include moving the detector manually or using an actuator. In an example, block <NUM> may be performed at least one of before, during, or after at least one of blocks <NUM>, <NUM>, or <NUM>.

The following working examples provide further detail in connection with the specific embodiments described above.

The agricultural spray of this Working Example <NUM> was formed by mixing XtendiMAX®, Roundup® PowerMAX®, Class Act® Ridion™, and OnTarget™ together. OnTarget™ is a proprietary drift reduction adjuvant that includes at least one rheology modifier. The product use rates of XtendiMAX® and Roundup® PowerMAX® in the agricultural spray of Working Example <NUM> were both <NUM>,<NUM>/ Km<NUM> (<NUM> ounces per acre). The amounts of Class Act® Ridion™ and OnTarget™ in the agricultural spray of Working Example <NUM> were <NUM> volume % and <NUM> volume %, respectively.

The test section of the wind tunnel shown in <FIG> was used to test the agricultural spray of Working Example <NUM>. The nozzle of the test section was a Wilger UR <NUM>. The agricultural spray of Working Example <NUM> was emitted from the nozzle at <NUM>,<NUM> bar (<NUM> pounds per square inch). The air flowing through the test section was held at a constant speed that simulated an ambient air speed of <NUM>,<NUM>/h (<NUM> mph) and a speed of the applicator of <NUM>,<NUM>/h (<NUM> mph) The spray orientation angle θ between air flowing through the test section and the spray sheet was <NUM>°.

<FIG> is an image of the spray sheet of agricultural spray of the Working Example <NUM> near the nozzle experiencing the bag rupture approach to droplet formation. In <FIG>, a bag is shown that has been formed in the agricultural spray of the Working Example <NUM> (indicated with arrow <NUM>). <FIG> also shows a bag in the process of rupturing (indicated with arrow <NUM>). Droplets formed from a ruptured bag (indicated with arrow <NUM>) is also shown in <FIG>. In other words, Working Example <NUM> demonstrates that the test sections disclosed herein may detect when the agricultural spray form droplets according to the bag rupture approach to droplet formation.

An agricultural spray of the Working Example <NUM> was provided. InterLock®, a propriety adjuvant that includes at least one perforation-aid type adjuvant, was added to the agricultural spray to form the agricultural spray of Working Example <NUM>. The agricultural spray of Working Example <NUM> was then sprayed into the test section of the wind tunnel shown in <FIG> using the same method as the agricultural spray of Working Example <NUM>.

Claim 1:
A wind tunnel having a test section (<NUM>, <NUM>, <NUM>, <NUM>), and
a blower (<NUM>) configured to provide air (<NUM>) to the test section, the test section comprising:
at least one surface (<NUM>, <NUM>, <NUM>) defining an at least partially enclosed space (<NUM>, <NUM>, <NUM>, <NUM>),
the at least partially enclosed space (<NUM>, <NUM>, <NUM>, <NUM>) defining an airflow path for air provided by the blower;
a flat fan nozzle (<NUM>) disposed in the at least partially enclosed space (<NUM>, <NUM>, <NUM>, <NUM>),
the flat fan nozzle (<NUM>) configured to spray an agricultural spray (<NUM>, <NUM>, <NUM>, <NUM>), in a spray sheet,
the spray sheet (<NUM>, <NUM>, <NUM>, <NUM>) exhibits a non-parallel spray orientation angle (Θ) measured clockwise from the spray sheet to the airflow path of the enclosed space,
wherein the agricultural spray includes a portion (<NUM>) initially exiting the flat fan nozzle that forms a continuous sheet-like portion defining an initial spray pattern;
at least one stimulus source (<NUM>, <NUM>, <NUM>, <NUM>) positioned to illuminate at least the portion (<NUM>) of the agricultural spray (<NUM>, <NUM>, <NUM>, <NUM>) exiting the flat fan nozzle (<NUM>), wherein the portion (<NUM>) of the agricultural spray (<NUM>, <NUM>, <NUM>, <NUM>) includes a region of the agricultural spray (<NUM>, <NUM>, <NUM>, <NUM>) initially exiting the nozzle (<NUM>) that forms the continuous sheet-like portion defining the initial spray pattern; and
at least one detector (<NUM>, <NUM>, <NUM>, <NUM>) positioned to image at least the portion (<NUM>) of the agricultural spray (<NUM>, <NUM>, <NUM>, <NUM>) exiting the flat fan nozzle (<NUM>).