How to get the same standard k-epsilon as CFX?
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The standard k-epsilon in Fluent differs from original standard k-epsilon by the fact that production of k differs: Gk=mu_eff* S^2 (for incompressible flow) instead of Gk=mu_turb* S^2 (for incompressible flow) mu_mol= molecular viscosity mu_turb= turbulent viscosity mu_eff=mu_mol+mu_turb S= strain rate magnitude Note that for epsilon source term C1epsilon*epsilon/k*Gk=C1epsilon*rho*Cmu *k*S^2, with Gk=mu_turb* S^2 You can retrieve the original behavior of standard k-epsilon which is coded in CFX with the following UDF: #include "udf.h" /* UDF to retrieve standard k-epsilon production */ DEFINE_SOURCE(k_source_mu_lam, c, t, dS, eqn) { real G_k; G_k=-C_MU_L(c,t)*C_STRAIN_RATE_MAG(c,t)*C_STRAIN_RATE_MAG(c,t); return G_k; } |
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