Hello everyone, I try to compute one on my fluid computation on Comsol but unfortunately I have the same error each time. When I use the laminar flow physics I can find a solution but when I use the high mach number flow physics my problem appears. This is the pop up message (Sorry the message is in french because I'm french but basically it says that "during the computation there is a non-integer power of a negative number") :
Etape ségrégée 2 Essai de calcul d'une puissance non entière d'un nombre négatif. - Fonction: ^ Echec dans l'évaluation de la variable. - Variable: comp1.hmnf.mu - Défini par: ((((comp1.T/comp1.hmnf.Tmu_ref)^1.5)comp1.hmnf.mu_ref)(comp1.hmnf.Tmu_ref+comp1.hmnf.S_s))/(comp1.hmnf.S_s+comp1.T) Echec dans l'évaluation de la variable. - Variable: comp1.hmnf.time_step_inv - Défini par: max(sqrt(emetric(comp1.u,comp1.v)((2^gmg_level)^2)),comp1.hmnf.mu/(((0.25comp1.hmnf.l_mix_lim)^2)comp1.hmnf.rho)) Echec dans l'évaluation de l'expression. - Expression: nojac(comp1.hmnf.time_step_inv/comp1.hmnf.locCFL) Echec dans l'évaluation de l'expression. - Expression: d((-comp1.hmnf.rhonojac(comp1.hmnf.time_step_inv/comp1.hmnf.locCFL)(comp1.ep-nojac(comp1.ep))test(comp1.ep))*(dvol),{test@2}) - Caractéristique: Solveur stationnaire 1 (sol1/s1)
I have join a screenshot of my geometry, it's a basic one but I need it. Eventually, my initial value is the mach on x-axis : M=4. The temperature doesn't change during the fluid flow.
Thank you for your help.