title: PIV applied to eckart streaming produced by a medical ultrasound transducer.
abstract: Particle image velocimetry (PIV) is applied for the first time to study Eckart streaming induced by a medical ultrasonic transducer operating at a frequency of 3.3 MHz and effective acoustic intensities of 0.25 and 3 Wcm(-2). A temporal series of velocities in a two-dimensional plane were recorded resulting in an experimental set comprising over half a million velocity data points. These enabled average and fluctuating properties to be determined and clearly indicated the quasi-steady nature of the flow. The average large scale velocity fluctuations along the axis caused by this quasi-steady property were calculated to be 2 and 20 m ms(-1) at effective intensities of 0.25 and 3 Wcm(-2) respectively corresponding to approximately 25% of the peak flow velocity in both cases. Furthermore averaged shear rates were calculated with peak values of 1 and 8 s(-1) 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 fluids.
authors.affiliation: Department of Physics and Astronomy, The University of Edinburgh, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Cosgrove
authors.forename: J M
authors.initials: JM
authors.lastname: Buick
authors.forename: S D
authors.initials: SD
authors.lastname: Pye
authors.forename: C A
authors.initials: CA
authors.lastname: Greated
mesh_terms: D012212:Rheology; D014159:Transducers; D014463:Ultrasonography / Q000379:methods*