Turbulence in super-high intensity standing wave field

Acoustic streaming in a standing wave field has been measured using Laser Doppler Velocimeter (LDV).If sound pressure level (SPL) of the standing wave tube is larger than 140dB,the stable and regular structure of acoustic streaming will distort apparently.As SPL improved on,vortex combining and breaking can be observed through flow visualization.Under super-high intensity of more than 160dB,it clearly changes to acoustic turbulence.The results of LDV show,following with the improvement of intensity,velocity spectra of some points broaden apparently,while others keep their original status.Results of turbulence intensity across the pressure node plane also show,the regular and symmetrical flow structures in the tube have been turned to turbulence.