PIV applied to Eckart streaming produced by a medical ultrasound transducer
✍ Scribed by J.A. Cosgrove; J.M. Buick; S.D. Pye; C.A. Greated
- Book ID
- 104263429
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 383 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0041-624X
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✦ Synopsis
Particle image velocimetry (PIV) is applied for the ®rst time to study Eckart streaming induced by a medical ultrasonic transducer operating at a frequency of 3.3 MHz and eective acoustic intensities of 0.25 and 3 W cm À2 . A temporal series of velocities in a twodimensional plane were recorded resulting in an experimental set comprising over half a million velocity data points. These enabled average and ¯uctuating properties to be determined and clearly indicated the quasi-steady nature of the ¯ow. The average large scale velocity ¯uctuations along the axis caused by this quasi-steady property were calculated to be 2 and 20 m ms À1 at eective intensities of 0.25 and 3 W cm À2 respectively corresponding to approximately 25% of the peak ¯ow velocity in both cases. Furthermore averaged shear rates were calculated with peak values of 1 and 8 s À1 for the low and high intensities respectively. The present investigation indicates the usefulness of PIV for such studies and serves as a prelude to investigations of streaming in biological type ¯uids.