# A Has anyone here studied cavitation? (acoustic streaming)

1. Jul 19, 2016

### rwooduk

Hi,

I am trying to distinguish the mechanisms for acoustic and quasi acoustic streaming during cavitation.

This is what I have written so far:

I have the quasi acoustic streaming pretty much sorted, it's just as a result of macroscopic applied frequency effects (flow) from the transducer. Its the acoustic streaming I'm struggling with! Is it like I have written above a direct result of bubble surface fluctuations?

For example for a bubble near a surface we have a boundary streaming effect with causes the bubble to collapse at the surface, which is a direct result of asymmetry of flow near the surface... BUT what is the assymetry of flow due to? The oscillations of the bubble?

I'm trying to figure out what exactly is causing this streaming in a cavitational environment.

Thanks for any ideas!

2. Jul 19, 2016

### rwooduk

ahhh its ok I found it

In the ‘‘genuine acoustic streaming’’, the
fluid motion is produced by the attenuation of the
acoustic wave during its propagation. In the ‘‘quasi-
acoustic streaming’’, fluid motion results from the gradi-
ent of the mean acoustic pressure, as a consequence of
nonlinear phenomena in the ultrasonic wave propaga-
tion.

edit errr maybe not, attenuation of the acoustic wave by what?

edit its okay, please feel free to delete this thread, it appears to be a result of a gradient of acoustic radiation pressure which results in a driving force. i was getting confused with the jetting effect due to boundary flow at an extended surface.

edit but, the bubble motion does influence the fluid due it its viscosity

Last edited: Jul 19, 2016
3. Jul 19, 2016

### rwooduk

ok I've updated my writing on this, hopefully its now correct, here for anyone interested:

Last edited: Jul 19, 2016