Hi everyone, I’m working on an IDDES simulation in OpenFOAM for a Formula car. My RANS simulation runs fine, and I’d like to use mapFields to take that solution as the initial condition for the IDDES run. From my understanding this should make sense, but please correct me if I’m wrong. I’ve also read that meshes designed for RANS are usually not suitable for LES. Would the same be true for IDDES? If so, what kind of modifications would be necessary? At this point I’m not really sure how to proceed. I’ve tried different setups, but the simulation always blows up. Below are the parameters I’ve modified in case someone can give me some guidance. The main issue I’m facing is with the Courant number. Should it always be < 1 for IDDES? Here’s how I tried to control it in controlDict: runTimeModifiable true; // allow controlDict to be read at each timestep adjustTimeStep true; // allow timestep to change based on maxCo deltaT 2e-6; // initial timestep value, adjustable at each iteration maxCo 1.0; // maximum CFL, deltaT changes based on this maxDeltaT 0.05; // upper limit for deltaT This gives acceptable values at the beginning, but after a while the CFL starts growing uncontrollably and the simulation diverges. Other parameters I’ve set are: LESModel: kOmegaSSTIDDES delta: IDDESDelta In fvSchemes: div(phi,U) Gauss DEShybrid linear // scheme 1 linearUpwind grad(U) // scheme 2 hmax 0.65 // DES coefficient, typically = 0.65 1 // Reference velocity scale 0.028 // Reference length scale 0 // Minimum sigma limit (0-1) 1 // Maximum sigma limit (0-1) 1; // B function limiter, usually 1e-03 div(phi,k) bounded Gauss upwind; div(phi,omega) bounded Gauss upwind; div((nuEff*dev2(T(grad(U))))) Gauss linear; Solver: PIMPLE In fvSolutions (under-relaxation factors): fields { p 0.3; } equations { U 0.7; k 0.7; omega 0.7; "(U|k|omega)Final" 1.0; } Any advice on how to stabilize the simulation or set this up properly would be really appreciated. Thanks in advance!