Title :
32 MHz Doppler assessment for streaming measurements
Author :
Nowicki, A. ; Secomski, W. ; Wojcik, J.
Author_Institution :
Dept. of Ultrasound, Polish Acad. of Sci., Warsaw, Poland
Abstract :
An approximate solution for the streaming velocity generated by flat and weakly focused transducers was derived by directly solving the Dirichlet boundary conditions for the Poisson equation. The theoretical calculations were verified using a purpose-designed 32 MHz pulsed Doppler unit. The applied average acoustic power was changed from 1 μW to 6 mW. The experiments were done on 4 mm diameter flat and focused transducers. The streaming velocity was measured along the ultrasonic beam from O to 20 mm. Streaming was induced in a solution of water and corn starch. The experimental results showed that for a given acoustic power the streaming velocity was independent of the starch density in water changed from 0.3 grams to 40 grams of starch in 1 litre of distilled water. For applied acoustic powers, the streaming velocity changed linearly from 0.2 to 40 mm/s. Theoretical solutions for both plane and focused waves agreed with experimental results
Keywords :
Doppler measurement; acoustic pulses; acoustic streaming; nonlinear acoustics; ultrasonic focusing; ultrasonic measurement; underwater sound; 0.2 to 40 mm/s; 1 muW to 6 mW; 32 MHz; 4 mm; Dirichlet boundary conditions; Gaussian beam; Poisson equation; acoustic wave propagation; average acoustic power; flat transducers; pulsed Doppler unit; starch density; streaming velocity; ultrasonic beam; water corn starch solution; weakly focused transducers; Acoustic beams; Acoustic transducers; Acoustic waves; Boundary conditions; Differential equations; Impedance; Navier-Stokes equations; Poisson equations; Ultrasonic transducers; Ultrasonic variables measurement;
Conference_Titel :
Ultrasonics Symposium, 1996. Proceedings., 1996 IEEE
Conference_Location :
San Antonio, TX
Print_ISBN :
0-7803-3615-1
DOI :
10.1109/ULTSYM.1996.584158
