Volkswagen sent a secondment to Inria with the purpose of the secondment is to tackle challenges of residual minimization-based model order reduction in car aerodynamics. To that end, a Reduced Order Model (ROM) based on residual minimization (ResMin-ROM) was applied to a backward facing step test case.
The work implemented in the secondment was on investigation of the “shift problem”: the minima of the objective function for the ResMin-ROM –calculated as some norm of the residual fields – and of the state vector error w.r.t. the full order model solution do not coincide
– Comparison of different ROM initial conditions, which revealed the presence of a local minimum
in the objective function
– Investigation of the weighing of bulk and boundary residuals
– Studying the effect of different norms for velocity and pressure