Stability analysis for flow control with porous media by Chloé Mimeau (CNAM, Paris)

The presence of a porous layer at the surface of an immersed body modifies the nature of the flow at the solid-porous-fluid interface. This modification may lead to flow regularization and the use of porous coatings is considered as a passive flow control technique. However the understanding of the physical mechanisms responsible for such flow regularization with porous media is still incomplete. This work adresses the following questions : Is a porous layer able to delay the transition to a more turbulent flow regime ? Is this delay monotonously related to the permeability of the added porous layer ?

To answer these questions, we propose a global stability analysis on solid cases (uncontrolled) and partially porous cases (controlled) in order to study the global modes of the resulting flows and to determine the ability of porous layers to delay flow bifurcations. This stability analysis will be performed on 2D and 3D cases, for the first flow bifurcations. An optimization strategy will also be proposed to identify relevant positions of the porous patches at the solid surface.