TOWARDS A BETTER PREDICTION OF AERODYNAMIC COEFFICIENTS IN AN IMMERSED BOUNDARY CONTEXT

International audience; This paper presents an improved immersed boundary method (IBM) with new wall model-ing assumptions for the simulation of compressible flows on Cartesian grids. This methodrelies on an adaptive positioning of both target and image points, in accordance with theReynolds number. It primarily ensures that the mesh is fine enough at the first computedcells to correctly capture the strong variations of the tangential velocity in the wall nor-mal direction, and ultimately prevents the appearance of spurious oscillations at the wall.In the present work, we take into consideration normal pressure gradient information,interpolated at a new set of image points positioned farther away from the geometry, inorder to extend the validity domain of our wall modeling. This significantly improvesthe prediction of the skin friction and the skin pressure coefficients, and also results in abetter estimation of both the drag and lift coefficients through the near-field integrationof all aerodynamic forces at the wall. The latest developments essentially consist in asecond-order extraction of the pressure at the wall during the post-processing step and amodification of Musker’s algebraic wall function to reconstruct the velocities and frictionat the target points at each iteration of the flow solver. This new methodology has beenvalidated through the study of subsonic flow simulations around a NACA0012 profile anda 3.5:1 prolate spheroid, where good agreements between the wall-modeled IBM solutionsand the body fitted wall-resolved references have been observed.