Progress on the Use of Compliant Walls for Laminar-Flow Control

Abstract

Thispaperreviewsand assessestherecentprogresstoward making theuseofcompliantwallsa practicalmethod of laminar-e ow control. Three main areas are covered. First, the current understanding of the vitally important e ow-induced surface instabilities is assessed. Some new results are included. Then the optimization of multiplepanel compliant walls is considered. New numerical simulation results are included showing that short compliant panels are very effective in suppressing Tollmien ‐Schlichting waves. It is found that for marine applications appropriately designed multiple-panel compliant walls are capable of suppressing Tollmien ‐Schlichting waves to indee nitely high Reynolds numbers. Finally, the feasibility of using compliant walls for laminar-e ow control in aeronautical applications is assessed. It is found that, although there is no reason in principle why compliant walls cannot be used in air, in practice exceptionally delicate walls are required to obtain the necessary match between thee uid and structural inertias. Theresulting lack ofrobustness forsuch walls isdeemed to make them completely impractical for aeronautical applications.