Design-Oriented Aerodynamic Analysis for Supersonic Laminar Flow Wings

The computation of boundary layer properties and laminar-to-turbulent transition location is a very complex problem, generally not undertaken in the context of aircraft design. Yet if an aircraft is to exploit the advantages of laminar flow and proper trade-offs between inviscid drag, structural weight, and skin friction are to be made, this is just what must be done. This paper summarizes a designoriented method for the aerodynamic analysis of supersonic wings including approximate means for estimating transition and total drag. The boundary layer analyses employed here are meant to be inexpensive but sufficiently accurate to provide some guidance for advanced design studies or to be incorporated in a multidisciplinary optimization. The boundary layer analysis consists of a quasi3D finite difference method, based on inputs from a 3D Euler analysis. A parametric fit of integral boundary layer properties to the amplification rate predicted by linear stability analysis, leads to a simplified method for predicting TS transition and the onset of instability of stationary crossflow modes. This simplifed boundary layer analysis and inviscid CFD were combined to evaluate the drag of a simple wing planform, defined by approximately ten geometric parameters. These parameters were used as design variables in a numerical optimization procedure to minimize total wing drag, illustrating the trade-offs between skin friction and inviscid drag. ∗Professor, Fellow AIAA †Graduate Student Copyright c ©2003 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc., with permis-