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-   -   compressibility and cavitation!! (http://www.cfd-online.com/Forums/cd-adapco/54417-compressibility-cavitation.html)

xhliu1 March 5, 2005 21:37

compressibility and cavitation!!
 
I have a problem with cavitation. The pressure dependent density description for the liquid works fine as long as I do not activate cavitation. But when activating the cavitation I get NaN for the produced species in the first Iteration (although there is no cavitation at the beginning of the simulation at all).

As I using the cavitation model,density of the heavy fluid just can be set as a constant number.Can I using some method to solve this problem?


Julien March 8, 2005 12:07

Re: compressibility and cavitation!!
 

Julien March 8, 2005 12:09

Re: compressibility and cavitation!!
 
Density of the heavy fluid is set constant by default. There is no other model in StarCD available at this moment.

xhliu1 March 9, 2005 01:54

Re: compressibility and cavitation!!
 
Thank you very much!! xhliu

carno March 9, 2005 03:51

Re: compressibility and cavitation!!
 
I am also facing same problem with cavitation in 3.22. The run is starting but after some iterations it is coming out. I have relaxed the problem very much still that problem is not vanishing. Does anybody else also face this problem with cavitationin 3.22. In 3.15 same case use to run very fine.

One strange thing is that I see different heavy fluid viscosity than what I specified. xhliu1 pls check this in your run file.


xhliu1 March 9, 2005 06:18

Re: compressibility and cavitation!!
 
carno,what I can say you is sorry,because I am using 3.15.

carno March 10, 2005 05:07

Re: compressibility and cavitation!!
 
Check your mesh. Hope the critical area has good quality cells.

xhliu1 March 14, 2005 01:11

Re: compressibility and cavitation!!
 
It works nothing! I can do the case of compressibility and cavitation separately very well!

carno March 15, 2005 05:49

Re: compressibility and cavitation!!
 
where such situation exists? I am just curious. U mean for vapour phase you are applying compressibility. I think only valid density setting is constant in this case. How u gave compressibility in cavitating flows.

xhliu1 March 15, 2005 20:52

Re: compressibility and cavitation!!
 
Thank you very much foe the reply!

Do you mean I should neglect the compressibility in case of cavitation?

But,in this case,the density of oil varies much with variety of pressure in the flow!

carno March 16, 2005 06:29

Re: compressibility and cavitation!!
 
In other words STARCD is not capable of solving cavitation with change in heavy fluid density situation. Local support may guide you more on this.

xhliu1 March 16, 2005 07:19

Re: compressibility and cavitation!!
 
Thank you!!

I have also see it in the reference of STARCD.But I want to see if there is another way to do this case.


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