Eigenspace-based sensitivity analysis of model-form uncertainty in subgrid-scale turbulence models*

Large-eddy simulation (LES) has gained significant importance as a high-fidelity reference technique for the resolution of complex turbulent flow. LES reduces the computational cost of solving turbulence by low-pass filtering the conservation equations. However, the effects of the small scales on the resolved flow field are not negligible, and therefore their contribution in the form of subgrid-scale stresses needs to be modeled. As a consequence, the assumptions introduced in the closure formulations result in potential sources of structural uncertainty that can affect the quantities of interest. Therefore, the aim of this work is to characterize their model-form uncertainty and its impact on the QoIs by means of recently developed eigenspace-based strategies. In the presentation, the strategy will be described in detail and investigations based on filtered direct numerical simulation and LES of turbulent free shear flows will be discussed.