Secondment from Volkswagen to International School for Advanced Studies (SISSA)

Markus Mrosek from Volkswagen had a secondment to International School for Advanced Studies (SISSA) in June 2022.


The purpose of the secondment is two-fold:

1) industrialize the previously developed multi-fidelity approach involving active subspaces (MF-AS) (;

2) investigate Reduced Order Models (ROM) based on residual minimization (ResMin-ROM) for
automotive vehicle aerodynamics with geometric parametrization.

The work implemented during the secondment includes:

  • Training in the python code for creating the MF-AS models, including the packages
    Emukit ( and ATHENA (
  • Comparison between MF-AS and Gaussian Process Regression in drag coefficient prediction accuracy on 11 industrial external aerodynamic datasets
  • Implementation of an automatic hyperparameter optimization procedure for the MF-AS ResMin-ROM
  • Investigation of the “monotonicity problem”: the objective function for the residual minimization – calculated as some norm of the residual fields – and the error of the ResMin-ROM with respect to the true solution do not always behave monotonically
  • Study effect of increasing number of snapshots (more full order simulations and/or more snapshots during the convergence of each full order simulation) on the monotonicity problem
  • Investigation of the weighting of velocity and pressure residuals

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