Acoustic streaming in lithotripsy fields: preliminary observation using a particle image velocimetry method.
This study considers the acoustic streaming in water produced by a lithotripsy pulse. Particle image velocimetry (PIV) method was employed to visualize the acoustic streaming produced by an electromagnetic shock wave generator using video images of the light scattering particles suspended in water. Visualized streaming features including several local peaks and vortexes around or at the beam focus were easily seen with naked eyes over all settings of the lithotripter from 10 to 18 kV. Magnitudes of the peak streaming velocity measured vary in the range of 10-40 mm s(-1) with charging voltage settings. Since the streaming velocity was estimated on the basis of a series of the video images of particles averaged over 1/60s, the time resolution limited by the video frame rate which is 1-2 orders of magnitude larger than driving acoustic activities, measured velocities are expected to be underestimated and were shown a similar order of magnitude lower than those calculated from a simple theoretical consideration. Despite such an underestimation, it was shown that, as predicted by theory, the magnitude of the streaming velocity measured by the present PIV method was proportional to acoustic intensity. In particular it has almost a linear correlation with peak negative pressures (r=0.98683, p=0.0018).
Choi
Min Joo
MJ
Department of Medicine, Cheju National University, 690-756, Republic of Korea. mjchoi@cheju.ac.kr
Doh
Doeg Hee
DH
Hwang
Tae Gyu
TG
Cho
Chu Hyun
CH
Paeng
Dong Guk
DG
Rim
Gun Hee
GH
Coleman
A J
AJ
D000162:Acoustics; D055590:Electromagnetic Phenomena; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation; D008096:Lithotripsy / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D011312:Pressure; D012212:Rheology / Q000379:methods; D012542:Scattering, Radiation; D014741:Video Recording; D014867:Water
D014867:Water