code_saturne User's Forum

Hello,

I have noticed that the source terms from the Merkle's model seem to be computed differently in the sources of the code. The Theory Guide v5.0.0 (page 145) indeed indicates the factor alpha * (1- alpha) instead of alpha for m- or 1- alpha for m+ according to the original model [1]. Moreover a recent PhD Thesis [2] indicates "By default, the model of Code_Saturne with cavitation module is a variation of the Merkle's model" and [3] seems to give the beginning of an explanation in Section 3.3 but it is unclear.

[1] Ding Li and Charles L. Merkle, A UNIFIED FRAMEWORK FOR INCOMPRESSIBLE AND COMPRESSIBLE FLUID FLOWS (2006)

[2] Christophe Leclercq, Simulation numérique du chargement mécanique en paroi généré par les écoulements cavitants, pour application à l’usure par cavitation des pompes centrifuges (2017)

[3] R. CHEBLI a,b , O. COUTIER -D ELGOSAH a , B. AUDEBERT b, Development of algorithm based on the fractional time
step for the simulation of cavitation.

Thank you in advance.

Regards,

So_nuc

Hello,

I just forwarded a link to you post to colleagues more familiar with this part of the code, so I hope they can provide the answers soon.

Best regards,

Yvan

Hello,

You are right, the cavitation source term model implemented in Code_Saturne differs from the original Merkle's model and the reason should be explain in ref [3] : it is because the alpha(1-alpha) factor makes the min/max principle (alpha must be between 0 and 1) is easier to satisfy with this formulation. I think Cdest=50 and Cprod=10000 constants were calibrated in order to take into account this modification in the source term.

I don't know if you have already modify some code_saturne source code but if you want to use the original Merkle model, I think you may just have to modifify the "cavitation_compute_source_term" routine in the cavitation.f90 file.

Best regards,
Benoît