Towards the Prediction of Fluctuating Wall Quantities Using Immersed Boundary Conditions

Abstract

Immersed boundary conditions (IBC) has reached a sufficient level of maturity to allow the simulation of compressible high Reynolds number flows around complex geometries. However, the reconstruction of physical quantities at the wall of geometries introduced using IBC is far from being straightforward. The difficulty to obtain a prediction as accurate as for classical body-fitted approaches originates from the intrinsic mismatch between immersed boundaries and the underlying mesh. To tackle this issue, a novel method to compute global loads and to provide precise wall data in the view of spectral analyses is introduced. First, this method is assessed for the investigation of highly unsteady separating compressible flows of two space launcher afterbody configurations using Zonal Detached Eddy Simulation (ZDES). Then, the results are compared against validated numerical simulations using a classical body-fitted approach. Finally, the present method successfully returns wall quantities with IBC consistent with classical methodologies and without additional time-consuming operations.