Periodic Rayleigh streaming vortices and Eckart flow arising from traveling-wave-based diffractive acoustic fields
Autor: | Kirill Kolesnik, Pouya Hashemzadeh, Wei Tong, Danli Peng, David J. Collins, Melanie E.M. Stamp, Morteza Miansari, Vijay Rajagopal |
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Rok vydání: | 2021 |
Předmět: |
Physics
Acoustics 010401 analytical chemistry 02 engineering and technology Acoustic wave 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Vortex Physics::Fluid Dynamics Standing wave Acoustic streaming symbols.namesake Transducer symbols Rayleigh scattering 0210 nano-technology Sound pressure Microscale chemistry |
Zdroj: | Physical Review E. 104 |
ISSN: | 2470-0053 2470-0045 |
Popis: | Recent studies have demonstrated that periodic time-averaged acoustic fields can be produced from traveling surface acoustic waves (SAWs) in microfluidic devices. This is caused by diffractive effects arising from a spatially limited transducer. This permits the generation of acoustic patterns evocative of those produced from standing waves, but instead with the application of a traveling wave. While acoustic pressure fields in such systems have been investigated, acoustic streaming from diffractive fields has not. In this work we examine this phenomenon and demonstrate the appearance of geometry-dependent acoustic vortices, and demonstrate that periodic, identically rotating Rayleigh streaming vortices result from the imposition of a traveling SAW. This is also characterized by a channel-spanning flow that bridges between adjacent vortices along the channel top and bottom. We find that the channel dimensions determine the types of streaming that develops; while Eckart streaming has been previously presumed to be a distinguishing feature of traveling-wave actuation, we show that Rayleigh streaming vortices also results. This has implications for microfluidic actuation, where traveling acoustic waves have applications in microscale mixing, separation, and patterning. |
Databáze: | OpenAIRE |
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