Abstract:

Aerodynamic sensitivity for subsonic lifting-surface with arbitrary curved leading edge is evaluated by kernal function method. The chordwise integration is carried out by an adaptive quadrature algorithm. Mangier principal value integral is calculated by Multropp method combined with subtracting points of singularity. The kernal of Mangier integral is expanded into an asymptotic expansion of chebyshef polynomials in order to assure the convergence of results. The expression of generalized force coefficients and the corresponding sensitivity derivatives are derived into very concise forms by means of an appropriate series representation for load distribution and the calculation of upwash velocity in Trefftz plane. Illustrative calculations for elliptic, rectangular and sweptback wings show that the force coefficient result of sensitivity derivative method are actually identical with that of direct kernal function method within the accuracy of lifting-surface theory, but the partial derivatives obtained hereby can be used for multidisciplinary optimization by decomposition for aircraft design.

Key words: lifing surfaces theory, subsonic flow, optimization