AERODYNAMIC SHAPE DESIGN FOR ROTOR AIRFOILS VIA GENETIC ALGORITHM

The Genetic Algorithm (GA) has been shown to be a useful tool in engin eering design problems. Here, the GA has been used to solve a helicopt er rotor airfoil design problem. A binary tournament, uniform crossove r GA was used in conjunction with a panel method I integral boundary l ayer method aerodynamic code. Twenty-one variables representing the su rface of the airfoil were operated on by the GA to maximize lift-to-dr ag ratio at three flight conditions representing the 75% radius statio n of an example rotor in forward flight with constraints on minimum li ft coefficient, maximum moment coefficient, and flow separation from t he airfoil. It was found that the GA could consistently design a non-t raditional airfoil to achieve its objectives, and that the resulting d esigns exhibited characteristics more favorable than the NACA 0012 sec tion of the original example rotor and the VR-7 section, While using t he genetic algorithm for shape design appears quite promising, an issu e with the study is that the quality of the results is a reflection of the accuracy of the aerodynamic analyses used; discussion is provided about this topic. The GA design methodology described in this study s hows promise for coupling with airfoil structural constraints and may lead to a more fully developed topology design approach.