Interaction of Boundary Layer and Suction Chamber of a Laminarization System

To investigate the interaction of Tollmien–Schlichting instabilities in a boundary layer over a porous surface with an underlying suction chamber, two-dimensional simulations solving the complete Navier–Stokes equations are conducted. It is found that the coupling of disturbances in the boundary layer and in the chamber leads to an increased mode amplification. The additional growth rate depends on the pore geometries, more generally on the impedance of the porous surface. It is shown that the amplitude growth is not dependent on the suction flow through the pores, assuming the boundary layer profile remains constant. This is realized by the use of source terms in the boundary layer. Furthermore, it is demonstrated that partitioning the chamber can mitigate the additional amplification. In this case, disturbances are prevented from propagating inside the suction chamber.