Accurate aerodynamic sensitivity analysis using adjoint equations

An accurate aerodynamic sensitivity analysis technique is described. The current method uses the continuous adjoint approach to avoid excessive memory requirement and the DADI relaxation with multigrid acceleration for the fast convergence. A derivation of the continuous adjoint operator is described for the 2nd-order TVD scheme and a new anti-diffusive flux is proposed for the adjoint equation to enhance the accuracy of sensitivity. The accuracy of current method is demonstrated by solving sensitivity problem for 2 dimensional airfoils. Comparisons are also presented with finite-difference results.