Numerical Optimization of Target Pressure Distributions for Subsonic and Transonic Airfoil Design.

摘要

Inverse aerodynamic design, calculating the geometry from prescribed pressure distributions, leaves the designer with the problem to define proper target pressure distributions. Numerical optimization techniques are employed to support the aerodynamic designer in the definition of target pressure distributions for subsonic and transonic airfoil design. A general parametric representation of airfoil pressure distributions is given, taking into account the physical characteristics of the airfoil flow. This parametric representation enables the designer to define 'optimum' target pressure distributions through numerical optimization techniques. Worked out examples show that a large class of airfoils can be described by the proposed procedure. The nature of the aerodynamic design problem appears to be such that best results are obtained with a simple line search method. In general, a large number of iterations is needed to arrive at the final (optimal) solution. However the requirement of a large number of iterations is not a serious drawback of the approach described in the paper. Finally, it is concluded that application of numerical optimization techniques is not (yet) to be considered as a routine job but considerable possibilities are offered to improve design results.