An unstructured full potential-integral boundary layer formulation

Abstract

The need for timely and appropriately accurate predictions of viscous, transonic flows for conceptual or preliminary aircraft design is addressed. The present formulation couples an existing three - dimensional, unstructured Full Potential formulation with a two - dimensional integral boundary layer method. A simplified strip wise representation of the three - dimensional boundary layer is used. The inviscid-viscous interaction is modeled using a wall transpiration boundary condition. The Full Potential formulation, the two - dimensional boundary layer formulation, and the inviscid-viscous coupling equations are all linearized and solved simultaneously using a preconditioned conjugate gradient squared type algorithm at each time step. The implicit formulation permits the solution of flows with separation without the need for an inverse type formulation. Results are presented for various two and three - dimensional flows, including a solution about a subsonic transport with an over the wing nacelle installation.