UNSTEADY AERODYNAMICS FOR ADVANCED CONFIGURATIONS. PART I. APPLICATION OF THE SUBSONIC KERNEL FUNCTION TO NONPLANAR LIFTING SURFACES

Abstract

Abstract : Equations for pressure distributions and generalized aerodynamic forces are derived for a thin nonplanar lifting surface in simple harmonic motion at subsonic speeds. A digital computer program, written in Fortran IV, is also presented. The computer program will generate up to a ten by ten matrix of generalized aerodynamic forces when given data for the geometry of a planar lifting surface with a folded planar tip, the flight Mach number, the reduced frequency of motion, and some control constants. Control surface deflections are not accounted for in the study. A kernel function method, which relates the pressure distribution to the downwash on a planar lifting surface, was extended and applied to a nonplanar lifting surface. Hsu's technique (PB-139 207) of employing Gaussian quadrature formulas is used when integrating the product of the kernal function and the lift function over the planform area. Recommendations are made to extend the method to account for blunted leading edges and the accompanying airfoil thickness and to account for control surface deflections.