CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   VOF Model or Mixture Model (http://www.cfd-online.com/Forums/fluent/73470-vof-model-mixture-model.html)

mems21 March 9, 2010 07:51

VOF Model or Mixture Model
 
Hi guys,

I'm modelling a valve with cavitation. The valve at the beginning is full of air.

So i have two mixture of fluids: water-vapor and water-air.

For cavitation, i've read Mixture Model is better but for water coming in a control volume with air, VOF Model suits better.

How would you do it with the same model for both situation??

Also, better transient or steady analysis?? cause the problem is that air never dissapears in the valve as it is to get water out of a dam, the suction of air is quite high.

Any ideas???

CFDtoy March 9, 2010 11:31

cav modeling
 
If you are doing cav modeling ...always go for mixture approach. Dont worry about the air..it wont predict cavitation in the air regions. The liquid-air interface may be smeared since its a mixture approach ..but we dont need that sharp interface (right?)..Steady unsteady both should be ok ..but for actual process itself...valve type..run unsteady to capture more transient effects.

/CFDtoy

Quote:

Originally Posted by mems21 (Post 249142)
Hi guys,

I'm modelling a valve with cavitation. The valve at the beginning is full of air.

So i have two mixture of fluids: water-vapor and water-air.

For cavitation, i've read Mixture Model is better but for water coming in a control volume with air, VOF Model suits better.

How would you do it with the same model for both situation??

Also, better transient or steady analysis?? cause the problem is that air never dissapears in the valve as it is to get water out of a dam, the suction of air is quite high.

Any ideas???


mems21 March 9, 2010 11:37

Thanks man!!!!

I will give a try the way you say.

I'm just scared that air can influence where cavitation happens. I'll let you know, if you don't mind.

C ya.


All times are GMT -4. The time now is 21:29.