Abstract:
A wave form tile in the form of a natural wave is provided to replace traditionally smooth surfaces to aid in more efficient shedding of a fluid medium. The wave form tile is also applied to proportionally spherical fractal surfaces defined for the surface of a vehicle.

Description:
RELATED APPLICATIONS 
     This application is a divisional of application Ser. No. 13/104,714 filed on May 10, 2011, which is incorporated herein by reference. Application Ser. No. 13/104,714 a continuation-in-part of application Ser. No. 11/484,212 filed on Jul. 11, 2006. Application Ser. No. 11/484,212 claimed the benefit of Provisional Application No. 60/698,454 filed on Jul. 11, 2005. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the field of fluid dynamic drag reduction. More specifically, the present invention pertains to techniques or devices for regulating the flow of air or water passing over a surface to reduce drag. 
     BACKGROUND OF THE INVENTION 
     The harnessing of engines to power vehicles at high speeds has created a need to cover powered vehicles with aerodynamically efficient surfaces that reduce drag. Reducing the drag resulting from the motion of an object through a fluid is one way to increase the efficiency of powered vehicles. Examples of previous attempts to reduce the drag of vehicle surfaces are taught in U.S. Pat. No. 5,114,099 by and U.S. Pat. No. 2,800,291 by Stephens et al. Although numerous attempts have been made to reduce the aerodynamic drag of surfaces, the applicant proposes that there are still significant opportunities for improvement in this field. 
     SUMMARY 
     Improved surfaces for reducing aerodynamic drag are configured to exploit the natural properties of a fluid as it moves over surfaces. By presenting the fluid with paths of least resistance it is possible to configure a surface that can move through a fluid with less resistance. In a first embodiment, an aerodynamic surface is covered with tiles waveform surfaces. In an example of the first embodiment, the tiles are generally rectangular or diamond shaped and are oriented such that each leading corner of each tile is oriented into the oncoming fluid stream, a trailing corner is oriented downstream and opposite side corners are arranged such that a line extending between them is generally normal to the direction of the fluid stream. In most examples, the fluid will be air and the surface will be covering a vehicle (such as an aircraft or land vehicle). The surfaces of the tiles are generally shaped as if a cresting wave had been mapped to the surface of the segment. The surfaces are shaped such that when a cross section is taken through each tile using a cross section plane that is generally normal to the overall surface and parallel to the general direction of the fluid flow (i.e. parallel to a line passing through the upstream and downstream corners of the segment), the cross section of each segment will have the form of an overturning or cresting wave. This will generally be the case regardless of where this cross section is taken. Accordingly, this general shape is constant if the cross section is taken near a side corner or if the cross section is taken at a center line between the side corners. This overturning wave form contour mimics the general shape assumed by fluid surfaces under high wind conditions and is believed to be a surface that presents paths of least resistance to the fluid flowing over that surface. This general form is mapped onto tiles that can then be arranged on a vehicle surface to define a vehicle surface which the applicant proposes will generate less drag than a traditional smooth vehicle surface. 
     In a second embodiment, the volume bounded by a vehicle is considered as a volume that can be filled with progressively smaller spheres. Thus, for example, with an automobile, a first sphere of the largest possible diameter is fit into the largest open space within the volume defined by the outside surfaces of the automobile. Next, smaller spheres are selected having diameters at a predetermined fraction of the diameter of the first sphere, for example 0.8 the diameter of the first sphere. These next smaller spheres are then fit into the remaining unoccupied spaces of the inside volume of the automobile. This process is continued until spheres are selected having diameters that are greater than a predetermined fraction of the diameter of the first sphere, for example 1/10th of the diameter of the first sphere and these smallest spheres are fit into the remaining spaces. After the volume has been filled with spheres as described above, a surface is defined by draping an imaginary flexible membrane over the spheres near the surface of the vehicle volume. This can be done with solid modeling software as would be well known by those skilled in the art. Still further, wave form surfaces may be mapped onto the spherical contour segments that are present on the outside surface of the vehicle as formed by the process described above. In this second embodiment, an vehicle surface is defined that presents less resistance to fluid flowing over the vehicle surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a plurality of tiles shown from the perspective of approaching fluid. 
         FIG. 2  is a perspective view showing a tile with four wave forms, like those shown in  FIG. 1  from a reverse angle perspective view. 
         FIG. 3  is a perspective view of the tiles of  FIGS. 1 and 2  shown from one side. 
         FIG. 4  is a side view showing how waves progressively form on the surface of a fluid as wind speed increases from condition A through condition D. 
         FIG. 5A  is a plan view of one wave form tile of an aerodynamic surface. 
         FIG. 5B  is a side view of the wave form tile of  FIG. 5A . 
         FIG. 5C  is a cross section view of the wave form tile of  FIG. 5A  taken from plane C-C of  FIG. 5A . 
         FIG. 5D  is a cross section view of the wave form tile of  FIG. 5A  taken from plane D-D of  FIG. 5A   
         FIG. 6  shows an elevation drawing of a wave form tile that could be applied to a square corner such as the corner of a rectangular trailer. 
         FIG. 7  shows a wave form tile the shape of a drip. 
         FIG. 8  shows a wave form tile the shape of a drip deformed at a generally right angle. 
         FIG. 9  shows a semi-trailer covered in wave form tiles. 
         FIG. 10  shows a first possible pattern of wave form tiles as applied to a fuselage shape. 
         FIG. 11  shows a second possible pattern of wave form tiles as applied to a fuselage shape. 
         FIG. 12  shows a third possible pattern of wave form tiles as applied to a fuselage shape. 
         FIG. 13  shows a wave form tile on a pick-up truck bed. 
         FIG. 14  shows the wave form tile pattern on a circular wheel shape. 
         FIG. 14A  shows a cross section of the wave form tile pattern on a circular wheel shape of  FIG. 14  taken from plane A-A indicated in  FIG. 14 . 
         FIG. 14B  shows a cross section of the wave form tile pattern on a circular wheel shape of  FIG. 14  taken from the arc shaped view indicated by B-B in  FIG. 14 . 
         FIG. 15  is a side profile view of an automobile. 
         FIG. 16  is a side profile view of an automobile with its internal volume defined by progressively proportioned spheres. 
         FIG. 17  is a side profile view of an automobile with its internal volume defined by progressively proportioned spheres and with the external surface segments of the proportioned spheres mapped with wave form surfaces. 
         FIG. 18  is a side profile view showing only the outline of an automobile with its internal volume defined by progressively proportioned spheres and with the external surface segments of the proportioned spheres mapped with wave form surfaces. 
     
    
    
     DETAILED DESCRIPTION 
     An improved aerodynamic surface  10  is shown in  FIG. 1 . As can be seen in  FIG. 1 , surface  10  includes a plurality of wave form tiles that includes wave form tiles  30 ,  32  and  34 . As can be seen in  FIG. 2 , each wave form tile has a surface that is topographically shaped in the form of an overturning wave. Wave form  20  shown in  FIG. 2  may be selected for closer consideration. As can be best seen by referring to  FIGS. 5A-5D , wave form tile  20  is shown to include a forward corner  34  and a rear corner  22 . 
     As can be best seen by referring to  FIGS. 2 ,  3  and  5 A- 5 D, the contour of the surface of wave form tile  20  includes two crest edges  38  and  40  that run down the trailing edges of tile  20  and meet at a curved crest portion  36 .  FIGS. 5C and 5D , which give cross sections taken from planes C-C and D-D indicate in  FIG. 5A , provide a way to visualize the general shape of tile  20  and the shapes of trailing edge portions  38  and  40  and crest portion  36  of tile  20 . As can be seen in  FIGS. 5C and 5D , the wave form defines a curved crest surface  40  which terminates in a crest edge  40 A. A symmetrically identical geometry is present for a curved crest surface  38  and a crest edge  38 A on the other side of plane C-C shown in  FIG. 5A . Recessed under crest edge  40 A is an undercutting portion  40 B which finally terminates in a lower edge  40 C. As can be seen in  FIGS. 5A ,  5 B and  5 C, these opposite trailing edge portions blend smoothly to define trailing crest portion  36  which is shown in profile in  FIG. 5B  and in cross section in  FIG. 5C . 
     The airflow across wave form tile  20  and by extension across a pattern of such wave form tiles as shown in  FIG. 2  will now be considered. When wave form tiles such as wave form tile  20  are, for example, disposed in a pattern on the surface of a vehicle, air flow will first encounter wave form tile  20  (as shown in  FIG. 5A ) at forward corner  34 A and along leading edges  34 A and  34 B. With reference to  FIG. 2 , air will be caused to flow from a forward corner  34  to a rear corner  22  across tiles,  20 ,  30 ,  28  and  32 . As the air travels across the surface of tile  20 , from corner  34 , it will first encounter the upper surfaces of wave  20 . When it encounters the upper surfaces of this wave form surface, it will be managed such that it is directed toward the general area of the forward crest  36  of the wave  20 . The air is guided by crest edges  38  and  40  and converges at some point proximate to crest portion  36  and generally above point  22 . Once the air has been directed in this manner so as to be concentrated proximate to crest portion  36 , the air traveling from wave form tile  20  will tend to move across tile  28  such that it is concentrated more toward the center line of wave form tile  28 . This produces channels of air-flow instead of the sheets of air which might occur when air is moving over a smooth surface. 
     If One skilled in the art were to consider wave form tile  20  in a generally upright orientation, one could visualize water running down wave form tile  20 . As a sheet of water runs down from forward edges  34 A and  34 B (shown in  FIG. 5A ) it adheres to drip edges  38  and  40  and then converges at point  36 , to become a unified stream. The unified stream of water leaving wave form tile  20  would then encounter wave form tile  28  near its midpoint. While remaining concentrated in a converged stream, the water would pass over wave  28  and flow from wave  28  in a similar fashion as it did wave form tile  20  leaving areas such as  22  untouched by water. Air and water are fluids, and at a conceptual level, will react in similar ways. 
     Relative motion of the entire device through the air (e.g., on the outside surfaces of a vehicle or airplane) will cause pressures in and around area  22  to be relatively higher than the areas of high wind exposure due to shielding or protection from the faster moving air. This elevation, or pooling, of pressurized air shields the surfaces of the tile from being directly contacted by the air traveling across the tile when the vehicle is in motion. Instead of engaging the tile surfaces, the lower pressure traversing air is repelled by the pressurized air. This air-to-air contact creates less drag than what would be air to vehicle surface contact with a conventionally smooth design. Therefore, drag is decreased and the vehicle travels with more aerodynamic efficiency. Of the numerous embodiments, the tile described in the present invention could easily be inverted and rotated 180 degrees, with area  22  in  FIG. 2  becoming the highest point of lowest pressure, and with 36 in  FIG. 2  becoming a recessed high pressure zone. High pressure pockets may also be built into a surface by constructing wave forms perpendicular to the flow of encountered fluid, like that of a shelf cloud on the front of a storm, preferably with an alternate undulation as  FIGS. 1 ,  2  and  5 A. The perpendicular wave form can be simplified to a continuous ring, of repeating wave forms as illustrated in  FIG. 11 , also including the recessed tubular wave form. 
     As relative wind speed increases, so do the surface waves of the fluid. As can seen in  FIG. 4 , as the wind speed increases from a calm condition as shown in condition A to a high wind condition as shown in condition D, surface waves become increasingly pronounced. In condition D, wave crests are being pulled leeward to the point the tip breaks off and becomes water spray. This may also be viewed as a physical molecular representation of the process of a liquid becoming gas on a boiling surface. The point at which the wave begins to break, a cavity, is formed, producing a high-pressure area/zone or cell. The tubular wave shaped cavity reacts with adjacent air to create alternating zones of high pressure which act to reduce the overall drag occurring the surface of the water. 
     Accordingly, by mimicking shapes in this naturally occur when fluids react with eroded surfaces or even when living organisms adapt to optimize the flow of fluid over surfaces, we are able to achieve a natural; cooperative interface between solids and fluids, by shaping the solid to resemble that of a fluid. 
       FIGS. 15-18  illustrate a process for patterning the surface of a vehicle which may be termed a spherical design proportioning system.  FIG. 15  shows a side profile of a typical automobile. The object here is to reshape the surface of this automobile into a surface that cooperates with airflow around the vehicle. As shown in  FIG. 16 , an automobile has outer surface which enclose an automobile volume  100 . A first sphere  102  is placed in the largest open space available in volume  100 . Thus, first Sphere  102  is preferably the largest sphere that can be placed within volume  100 . A second sphere  103  is placed in the next largest unoccupied space in volume  100 . As can be seen in  FIG. 16 , second sphere  103  is smaller than first sphere  103 . The process continues with a third sphere  104  and a fourth sphere  105  and numerous smaller spheres. The spheres used preferably progressively decrease in diameter. Moreover, it is preferable that each decrease in diameter be governed by a constant ratio. So for example, second sphere  103  may have a diameter of 80% of the diameter of sphere  102 . Third sphere  104  may have a diameter of 80% of the diameter of second sphere  103  and so on. This progression of decreasing diameters is preferably terminated at a predetermined minimum diameter of, for example, 1/10th the diameter of first sphere  102 . 
     Next, as can be seen in  FIG. 16 , a flexible membrane  200  is draped over the spheres to define a new, spherically proportioned surface. This surface includes a multitude of spherical hills  202  or bumps that are separated from each other by smooth transitioning valleys  204 . Thus between the troughs of adjacent valleys are defined spherical zones which are arranged over the surface of vehicle  100 . Those skilled in the art will appreciate that this modeling exercise may be conducted using computer aided design systems. This process conceptually relates to the use of fractal geometry to define naturally appearing structures such as mountain ranges and the like. In essence, a spherically proportioned surface is a fractal surface defined by progressively smaller spheres with a lower bound defined for the smallest spheres used to define the surface. 
     Once the spherically proportioned surface has been defined for the vehicle, it is possible, as shown in  FIGS. 17 and 18  to topographically map a pattern of proportionally sized wave forms on to the pattern of spherical zones  202 . As noted above, the spherical zones or tiles are bounded or defined by the troughs of the valleys between the zones. By combining this proportionally arranged spherically patterned surface with the wave form concept described above, it is possible to define a vehicle surface that is proposed to be optimized for reducing drag. Moreover, it is also possible to design vehicles capable of holding spherical tanks suitable for storing pressurized air which would provide a further benefit of providing an alternative energy source for the vehicle. Still further, it may be possible to create a vehicle having a relatively low coefficient of drag that also retains the general familiar shape of a typical automobile. 
     The centers of three spheres of equal size, when the surfaces of the spheres are in contact with each other, will define an equilateral triangle having 60 degree angles. When a fourth sphere is added to the pattern, the centers of the four spheres define the corners of a regular tetrahedron. If a volume is filled with spheres as described above, and, if the spheres in the volume define a matrix of tetrahedrons, much as in a crystalline structure, then the surface of such a volume is likely to have diamond shaped areas. Accordingly, when mapping a pattern of proportionally sized wave forms onto spherical zones  202  as shown in  FIGS. 17 and 18 , such zones could have a diamond shape such that the wave forms mapped upon them would be distorted toward a diamond shape having a leading corner with an angle of less than 90 degrees which differs from the square tile configuration shown in  FIG. 2 . 
     The skilled reader should appreciate that the above described surfaces may also be applied to other moving objects for which air resistance is a factor. For example, a car top mounted luggage container may be given a wave form surface such as shown in  FIGS. 1-3  or  FIG. 18 . Moreover, other surfaces of vehicles may be retrofitted with elements having wave form surfaces in order to add storage for the vehicle without increasing or even decreasing air resistance. 
     It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof.