# A Entrainment Coefficient - Dynamics of Fluids

1. May 11, 2017

### Wall

Hi all,

I'm studying the motion of a plume fluid in a fluid ambient, with ρ(plume) > ρ(ambient).
Afterwards there si a transport of fluid ambient as an effect of the turbolence caused by the viscosity between the two fluids.
This is, somehow, featured by the Alpha coefficient (entrainment)

My request is: can you explane to me, what physically represent this number? What i have to imagine when i want to figure out the entrainment? Wich is the formule?

2. May 16, 2017

### PF_Help_Bot

Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.

3. Oct 4, 2017

This is a rather niche topic within fluid mechanics. Have you tried checking out any relevant research papers or textbooks on the topic?

4. Oct 4, 2017

### Wall

Effect of Background rotation in turbulent line plumes
H. J. S. Fernando and C. Y. Ching

Development of a point plume in the presence of background rotation
H. J. S. Fernando, R-r. Chen, and B. A. Ayotte

The motion of Turbulent thermal in the presence of background rotation

Barbara Anne Ayotte and Harindra J. S. Fernando

I think i did understand what the entrainment is, but i dont its formula. I mean, i dont know its definition.

5. Oct 4, 2017

Variable-density turbulence is an active area of research and is what is occurring in the situation you outline, but the specifics of your plume situation and its related analysis are not something with which I have any experience.

I do know of one recent paper about experiments on turbulent jets with differing densities. I don't know if this work would be relevant directly to what you are doing, but perhaps it could point you in the right direction.

dx.doi.org/10.1017/jfm.2017.379

6. Oct 4, 2017

### Wall

Thank you so much, and thank you for your time, it will help me for sure!