A three dimensional, forward-marching, viscous flow analysis is applied to the tip vortex generation problem. The equations include a streamwise momentum equation, a streamwise vorticity equation, a continuity equation, and a secondary flow stream function equation. The numerical method used combines a consistently split linearized scheme for parabolic equations with a scalar iterative ADI scheme for elliptic equations. The analysis is used to identify the source of the tip vortex generation process, as well as to obtain detailed flow results for a rectangular planform wing immersed in a high Reynolds number free stream at 6 degree incidence.

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A viscous flow analysis of the tip vortex generation process

High-Angle-of-Attack Flying Qualities - An Overview of Current Design Considerations

: A hybrid viscous/potential flow program was developed to analyze the flow field on and around a swept thick wing with rounded leading edges and leading edge vortex flow. The program provides a computational package which includes four major programs run with proper interfacing in an iterative cycle. These programs include two viscous programs and two potential flow programs. The viscous flow programs consist of: (1) a parabolic solution to the Navier-Stokes vorticity equation in a box around the leading edge vortex; and (2) a three-dimensional second-order boundary layer program for infinite yawed wings. This program provides the boundary layer vorticity being fed into the vortex box. The two potential flow programs are: (1) the Hess surface singularity method for thick wings and fuselage combination; and (2) a vortex lattice method to model the leading edge vortex. These two programs provide the surface pressures and the viscous box boundary velocities. The program interfaces are developed by applying the concept to a 65 deg delta wing with a spanwise variation in leading edge radius. Operating experience is presented, giving the results and knowledge gained in each cycle of the iterations. The method allows the designer to design or modify the leading edge shape to meet the desired performance and control requirements.

Charles J Dixon

Papers

Development of a Viscous Vortex/Wing Interaction Program for Thick Wings with Rounded Leading Edge.