Rapid design space approximation for two-dimensional transonic aerofoil design

This paper presents a strategy for exploring the design space for use in aerodynamic optimization. This is achieved by perturbing the values of the geometric shape variables, angle of attack, and freestream Mach number for a 2D transonic aerofoil. The approach uses the ’quasi-analytical’ method, which arises from the direct differentiation of the nonlinear governing equations. Using only one traditional CFD analysis, the design space can be explored cheaply with little loss in accuracy for small perturbations. This approach is extended further by developing a new technique by applying the ’quasi-analytical’ method to provide information at selected positions in the design space and then to the approximation of the function for the aerodynamic quantities by a series of polynomials. This provides a significant cost reduction and simplifies the integration within modern engineering methods. Results are presented for a typical transonic airfoil, giving comparisons with individual CFD analyses. (Author)