Search query: Bubble Image Velocimetry with an Acoustic Camera

Related papers:

abstract: BACKGROUND: BIV is a subset of particle image velocimetry (PIV) a common laboratory experimental technique used to measure flow velocity. In traditional particle image velocimetry, the flow of interest is seeded with tracer particles that reflect light and are assumed to faithfully follow the motion of the fluid, which is a valid assumption with sufficiently small particles (Adrian and Westerweel 2011) In BIV, bubbles are used in place of tracer particles (Ryu et al. 2005) In either case, the motion of the tracer particles/bubbles is observed generally with a charge coupled device or complementary metal oxide semiconductor digital camera for modern systems and used to quantify the flow velocity. The flow velocity is measured by sub dividing the camera images into windows (e.g. 16 x 16 pixels) then, cross correlation is used to determine the aggregate displacement of all the particles in each window between successive images (Raffel et al. 2007) However, traditional PIV and BIV measurement techniques with an optical camera are difficult to deploy in the field because they are equipment intensive, require stationary, well calibrated images, and can only be performed in a reasonably transparent fluid (such that the optical camera can see the tracer particles/bubbles) Obviously these requirements quickly become restrictive in field deployments, particularly in highly turbid environments near dredging operations.
author_names: David L Young

Brian C McFall

Duncan Burnette Bryant
title: Bubble image velocimetry with an acoustic camera
year: 2019

abstract: BACKGROUND: BIV is a subset of particle image velocimetry (PIV) a common laboratory experimental technique used to measure flow velocity. In traditional particle image velocimetry, the flow of interest is seeded with tracer particles that reflect light and are assumed to faithfully follow the motion of the fluid, which is a valid assumption with sufficiently small particles (Adrian and Westerweel 2011) In BIV, bubbles are used in place of tracer particles (Ryu et al. 2005) In either case, the motion of the tracer particles/bubbles is observed generally with a charge coupled device or complementary metal oxide semiconductor digital camera for modern systems and used to quantify the flow velocity. The flow velocity is measured by sub dividing the camera images into windows (e.g. 16 x 16 pixels) then, cross correlation is used to determine the aggregate displacement of all the particles in each window between successive images (Raffel et al. 2007) However, traditional PIV and BIV measurement techniques with an optical camera are difficult to deploy in the field because they are equipment intensive, require stationary, well calibrated images, and can only be performed in a reasonably transparent fluid (such that the optical camera can see the tracer particles/bubbles) Obviously these requirements quickly become restrictive in field deployments, particularly in highly turbid environments near dredging operations.
author_names: David L Young

Brian C McFall

Duncan Burnette Bryant
title: ERDC/TN DOER I7 "Bubble Image Velocimetry with an Acoustic Camera"
year: 2019

author_names: David L Young

Brian C McFall

Duncan Burnette Bryant
title: Bubble image velocimetry with a field deployable acoustic camera
year: 2018

abstract: A drop impacting on a liquid surface may entrain a bubble resulting in sounds from the bubble oscillation in addition to that of the initial drop impact. This subject has received considerable interest with respect to the underwater sound produced by rain. The previous optical and acoustical studies have extensively examined the role of drop size and impact velocity as well entrainment formation mechanisms. However, the role of surfactants on the liquid surface has received less attention especially with respect to sound production. One previous study [1] of two different surfactants (Kodak Photoflo and a sulfo detergent) reports that these suppress entrainment resulting in diminished or negligible bubble noise. However, we have found bubble entrainment and acoustic emissions associated with the addition of a heptane layer on the water surface. Using a synchronized hydrophone and a high speed camera, acoustical and optical data of the bubble drop dynamics were obtained. Particle image velocimetry (PIV) was also utilized to measure the surface velocity produced by the drop. These results show a significant difference in the drop rebound and subsequent fluid column dynamics, which results in a dual acoustic emission for the surfactant case.Copyright (c) 2010 by ASME
author_names: Christopher N Layman

John Stefan Allen

In Mei Sou
title: Influence of Surfactants on Bubble Entrainment
year: 2010

abstract: Theory of cross correlation analysis of PIV images. Decay of rotating turbulence: Some particle tracking experiments. Measurement of product concentration of two parallel reactive jets using digital image processing. Image analysis of oil film interferometry a method of measuring wall shear stress distributions. Recent advances in LSV, PIV and PTV. Development of particle image velocimetry: A new computation method with directional resolution. Algorithms for automatic measurements of size and velocity of spray droplets from holography reconstructions. Characterization of Savonius rotor wake using image analysis processing techniques. An application of image processing methods to determine the critical shear stress in sewer systems. A three dimensional particle image velocimetry system and its application to the measurement of acoustic streaming. A camera for measuring density, size and velocity of rising air bubbles and water velocity in a bubble plume. The application of PIV to turbulent two phase flow. A critical analysis of the particle image velocimetry technique as applied to waves. A colored method for PIV technique. Digital PIV applied to flows around artificial heart valves: Analysis by autocorrelation.
author_names: F T M Nieuwstadt
title: Flow visualization and image analysis
year: 1993

abstract: The bubble image velocimetry (BIV) technical was implemented in a large wave basin for the first time to study its feasibility of measuring velocities in a greenwater flow. The greenwater flow was generated by the impingement of a plunging breaking wave onto a horizontal model deck formed by a square plate. A LED panel was used as the deck and the light source of the BIV system. A high speed camera was used to record images for BIV velocity determination. Measurements taken in the large model basin were used to compare with measurements taken in a small wave tank in a laboratory for examining the scale effect.
author_names: Kuang-An Chang

Youn Kyung Song

Kusalika Ariyarathne

Richard Mercier
title: Greenwater Velocity Measurements In a Large Scale Wave Basin Using Bubble Image Velocimetry
year: 2012

abstract: Abstract The ultrasonic assisted water confined laser micromachining is a novel micromachining method. This paper reports the experimental studies of ultrasonic power and water layer thickness on the laser (1064 nm nanosecond pulse laser) micromachining of silicon. Besides, this reports a systematic discussion on the influence of the acoustic streaming and bubbles (induced by laser) dynamic change on the machining process. The acoustic streaming and flow pattern under different ultrasonic power application and different water layer thickness using Particle Image Velocimetry (PIV) A finite element (FE) heat transfer model was employed to gain a better understanding of the effect of the acoustic streaming velocity on the temperature field change in laser processing. The bubbles (induced by laser) dynamic behavior is observed by the high speed camera. The results showed that the ultrasonic assisted laser ablation can yield much higher the material removal rate than laser cutting in water without ultrasonic assisted. Besides, the increase in the ultrasonic power helps to improve the etching efficiency but is not apparent. When the water layer thickness is 1 mm, the cutting effect is significantly different from the laser ablation in the other three water layers. Through the PIV images and simulate results, it has been found that the influence of acoustic streaming on heat transfer in laser processing is small. Through high speed camera imaging observations, the dynamic change of bubbles is an essential mechanism for the enhanced material removal rate and affect the machining performance in this study. This study helps understand the mechanism of ultrasonic assisted water confined laser micromachining better and promoting this technique potential application in the micromachining of hard brittle materials.
author_names: Jia Zhou

Rongwei Xu

Hui Jiao

Qing-yuan Liu

Yuhong Long
title: Study on the mechanism of ultrasonic assisted water confined laser micromachining of silicon
year: 2020

abstract: Abstract A plunging breaking wave of 1 m height was generated in a very large wave tank of 5 m in width, 5 m in depth, and 300 m in length filled with freshwater. The surface velocities in the highly aerated region of the breaking wave were measured using bubble image velocimetry (BIV) while the void fraction profiles were measured using fiber optic reflectometers (FOR) The internal velocities below the aerated region were also measured using an array of acoustic Doppler velocimeters (ADV) A wavelet based technique was used to detect vortical structures at the free surface and estimate their length scales. The measured surface velocity fields were decomposed into wave induced and turbulence induced components to investigate the temporal and spatial evolution of mean kinetic energy and turbulent kinetic energy. It was found that turbulence is advected and diffused mainly following the phase speed of the breaking wave, rather than from the wave group velocity during the first splash up process. The internal velocity measurements below the aerated regions show that turbulent kinetic energy decreases exponentially as the depth increases. Since scale effects under breaking waves with turbulence and air entrainment are less understood, results in flow kinematics, turbulence, and void fraction in the present study were compared with that in Lim et al. (2015) which investigated small scale plunging breaking waves with a 0.2 m wave height. It was found that flow kinematics and some dynamic properties such as void fraction and turbulent kinetic energy can be well represented between different physical scales if the traditional Froude scaling law is applied. Other dynamic properties, including bubble number and size distributions, seem to be significantly affected by the physical scales.
author_names: Byoungjoon Na

Kuang-An Chang

Zhi-Cheng Huang

Wen Yang Hsu

Wei-Liang Chuang

Yang-Yih Chen
title: Large scale laboratory observation of flow properties in plunging breaking waves
year: 2018

abstract: A number of acoustic and fluid dynamic phenomena appear in ultrasonic cleaning baths and contribute to physical cleaning of immersed surfaces. Propagation and repeated reflection of ultrasound within cleaning baths build standing wave like acoustic fields; when an ultrasound intensity gradient appears in the acoustic fields, it can in principle induce steady streaming flow. When the ultrasound intensity is sufficiently large, cavitation occurs and oscillating cavitation bubbles are either trapped in the acoustic fields or advected in the flow. These phenomena are believed to produce mechanical action to remove contaminant particles attached at material surfaces. Recent studies suggest that the mechanical action of cavitation bubbles is the dominant factor of particle removal in ultrasonic cleaning, but the bubble collapse resulting from high intensity ultrasound may be violent enough to give rise to surface erosion. In this paper, we aim to carefully examine the role of cavitation bubbles from ultrasonic cleaning tests with varying dissolved gas concentration in water. In our cleaning tests using 28 kHz ultrasound, oxygen supersaturated water is produced by oxygen microbubble aeration and used as a cleaning solution, and glass slides spin coated with silica particles of micron/submicron sizes are used to define cleaning efficiency. High speed camera recordings and Particle Image Velocimetry analysis with a pressure oscillation amplitude of 1.4 atm at the pressure antinode show that the population of cavitation bubbles increases and streaming flow inside the bath is promoted, as the dissolved oxygen supersaturation increases. The particle removal is found to be achieved mainly by the action of cavitation bubbles, but there exists optimal gas supersaturation to maximize the removal efficiency. Our finding suggests that low intensity ultrasound irradiation under the optimal gas supersaturation in cleaning solutions allows for having mild bubble dynamics without violent collapse and thus cleaning surfaces without cavitation erosion. Finally, observations of individual bubble dynamics and the resulting particle removal are reported to further support the role of cavitation bubbles as cleaning agents.
author_names: Tatsuya Yamashita

Keita Ando
title: Low intensity ultrasound induced cavitation and streaming in oxygen supersaturated water: Role of cavitation bubbles as physical cleaning agents.
venue: Ultrasonics sonochemistry
year: 2019

abstract: Abstract The present study employed the image based bubble image velocimetry (BIV) technique to investigate the flow kinematics of a plunging breaking wave impinging on a geometry simplified, unrestrained tension leg platform (TLP) A high speed camera was used to record images for the BIV velocity determination for both fluid and structure velocities. The plunging breaker was generated using a wave focusing method, and repeated measurements were acquired to calculate the mean flow and turbulence intensity using ensemble averaging. BIV measurements were performed on two perpendicular planes: side view and top view. The flow measurements were compared with those of a similar experiment on a fixed structure by Ryu et al. (Exp Fluids 43(4):555 567, 2007a) The maximum velocity occurred in the run up stage with a magnitude reaching 2.8C with C being the phase speed of the breaking wave. The dominant velocities for three distinct phases impingement, run up, and overtopping are very close to those found on the fixed structure. Turbulence intensity was also examined, and the ratio among the three components was quantified. Ryu et al. (Appl Ocean Res 29(3):128 136, 2007b) reported that Ritter's dam break flow solution agrees surprisingly well with the measured green water velocity on the fixed structure to a certain degree. The present study followed the same approach and confirmed that Ritter's solution is also in excellent agreement with the green water velocity on the unrestrained TLP model. Based on the self similar behavior, the prediction equation proposed by Ryu et al. (2007a) was used to model the green water velocity distribution. The results show that the prediction equation is applicable to not only a fixed structure, but also the unrestrained TLP for green water velocity caused by extreme waves.
author_names: Wei-Liang Chuang

Kuang-An Chang

Richard Mercier
title: Green water velocity due to breaking wave impingement on a tension leg platform
year: 2015