Experimental study of acoustic streaming in a high level standing wave guide: influence of mean temperature and higher harmonics distribution

Streaming velocity in an acoustic standing waveguide is measured using Laser Dopper Velocimetry (LDV) from low to high acoustic amplitudes. As expected, the axial streaming velocity agrees with the slow streaming theory for low amplitudes but deviates significantly from such predictions for fast streaming. For high amplitudes, an additional outer streaming cell appears; the structure of the streaming vortices is more complex but maintains a certain consistency, symmetry and keeps stable. Different factors that can be causing such mutation of streaming pattern are discussed such as the effects of temperature gradients and the non-linear propagation in the guide.