Control surface effectiveness in the transonic regime

Abstract

This paper investigates control surface effectiveness in the transonic flight regime. Linear and nonlinear aeroelastic analyses are performed while including the effects of flow viscosity with an interactive boundary layer in the prediction of this aeroelastic parameter. Transonic small-disturbance theory is employed in the analysis of a simple rectangular wing to study the interactions among control surface deflections, structural flexibility, and embedded shocks in a flow field where a viscous boundary layer exists. Pressure distributions on the wing are examined and control surface reversal calculations are presented. These results are discussed based on the predictions of the pressure coefficients generated by the solution of the transonic small-disturbance equation. A limited number of Euler computational fluid dynamic solutions are presented for purposes of comparison of inviscid transonic smalldisturbance results with a higher order CFD code. Generalizations are offered concerning the effects of including viscosity in the prediction of steady aeroelastic phenomena in the transonic flight regime. The adequacy of using transonic small-disturbance theory in the prediction of transonic airloads as compared to Euler CFD analyses is considered. Finally, the consequences of these findings on the preliminary design of aircraft structures are discussed.