Cavitating Foam: need a clarification with the thermodynamic properties dictionary
 

Hi,

I'm a new user in openfoam and require to work with cavitating foam. My question is very simple, i need a calrification with the thermodynamic properties dictionary. What do the the variables "psiv" and "psil" signify and where are they used in the actual code?

Please help!

thnX!!

Hi, I think the answers are in this link:

http://www.cfd-online.com/Forums/ope...psil-psiv.html

l = is referred to the liquid
v = is referred to the vapor

I hope it would work

Gaby

Hi,

Thanks gaby!

also i would like to know the value of psiv for a vapour like air. How can it be calculated?


thnX!

Hi Foamers!
I have a problem in running the cavitatingFoam solver in version 1.6 and 1.6.x.

It works only if there is no cavitation...as soon as it cavitates (gamma is no longer 0), the pressure becomes negative.
Furthermore when the compressibility of the fluid is increased the density appears to burst, as the output indicates non-realistic values.

Have you encountered the same problem while running a simulation?

I think the problems can be due to the assumption made in the paper describing the solver by Karrholm that the compressibility is constant, but this does not hold when the cavitating parameter(gamma) changes with time. Is my understanding of the assumption true?

Thank you !

Marta

crash in cavitatingFoam tutorial case
 

Hi,
I'm testing the cavitatingFoam(ras) code of version 2.3.0 but it crash when I run it and without make any change in tutorial case. Anyone familiarized with this solver could help me?
Thanks in advance.

HI alvaro,

I am not really familiarized with cavitatingFoam, but I tried it myself ashort time ago and experienced the same problems.

I think the problem is not stable behaviour when the grid has small cells.
You can try the tutorial with commenting out the refinemeshByCellset line from the Allrun script. Or delete just the 2 and 3 in that line...

I don't know if LES worked better... Right know I do the mostly same things with InterPhaseChangeFoam, because it works smoother and gives better results.

regards
Alex

Hi Alex,
Thank you for reply. I solved the problem finally. I just had to low the maxCo and maxAcusticCo and the simulation worked without problem (and more slowly). I tested with different size of cells modifying the Allrun script as you said and you were right, the behaviour si more stable. Now I'm going to try run with my own geometry (axi-symmetry nozzle) with cavitatingFoam and interPhaseChangeFoam and then compare the results. Thanks for your advice.
Regards,
Alvaro.

Dear Alvaro,

Did you get the results? Could you please share them to me to make me clarified about the differences between two solvers?

Thank you and best regards,

Tung