Computational Study of Shock-buffet on 3D Wings

摘要

The paper presents a computational study of the transonic shock-rnbuffet flow instability phenomenon on three-dimensional wings. Reynolds-rnaveraged Navier-Stokes simulations were conducted on three wing con-rnfigurations, all based on the RA16SC1 airfoil, at shock-buffet flow con-rnditions. The simulated configurations include Infinite-straight, Infinite-rnswept and Finite-swept 3D wing models of several sweep angles and spanrnlengths. Based on the results, the effects of 3D flow, wing-sweep andrnspan-length on the shock-buffet characteristics are identified. For smallrnwing sweep angles the fundamental shock-buffet instability mechanismrnremains similar to the 2D mechanism, which is characterized mainlyrnby chordwise shock oscillations. For moderate sweep angles, a phe-rnnomenon of lateral pressure disturbance propagation is observed. Thisrnphenomenon is essentially different from the 2D shock-buffet mechanism,rnyet results in oscillations of the sectional aerodynamic coefficients. Thernpaper presents and discusses both phenomena, and suggests a connectionrnbetween them. For high wing sweep angles the wing is stalled and shock-rnbuffet is eliminated. For low aspect-ratio wings, the flow is dominatedrnby tip vortices, and shock-buffet is eliminated. For high aspect-ratiornwings, wingtip effects are minor and limited to the tip region. For in-rntermediate aspect-ratio cases, tip vortices and shock-buffet interactionrnresults in irregular shock oscillations.