论文信息 - Some Advanced Concepts in Discrete Aerodynamic Sensitivity Analysis

Some Advanced Concepts in Discrete Aerodynamic Sensitivity Analysis

Abstract 1.0 Introduction An efficient incremental-iterative approach for dif-ferentiating advanced flow codes is successfully demon-strated on a 2D inviscid model problem. The methodemploys the reverse-mode capability of the automatic-differentiation software tool ADIFOR 3.0, and isproven to yield accurate first-order aerodynamic sensi-tivity, derivatives. A substantial reduction in CPU timeand computer memory is demonstrated in comparisonwith results from a straight-forward, black-box t:everse-mode application of ADIFOR 3.0 to the same flowcode. An ADIFOR-assisted procedure for accurate sec-ond-order aerodynamic sensitivity derivatives is suc-cessfidly verified on an inviscid transonic lifting airfoilexample problem. The method requires that first-orderderivatives are calculated first using both the fonvard(direct) and reverse (adjoint) procedures; then, a veryefficient non-iterative calculation of all second-orderderivatives can be accomplished. Accurate second de-rivatives (Le., the complete Hessian matrices) of lift,wave-drag, and pitching-moment coefficients are calcu-lated with respect to geometric-shape, angle-of-attack,and freestream Mach numberComputing sensitivity derivatives (SDs) from high-fidelity, nonlinear CFD codes is an enabling technologyfor design of advanced concept vehicles. In recent yearssignificant progress has been achieved in the efficientcalculation of accurate SDs from these CFD codes _.-The automatic differentiation (AD) software toolADIFOR (Automatic Differentiation of FORTRAN)has been proven an effective tool for extracting aerody-namlc

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