Genetic algorithm based constrained optimisation for laminar flow control

A significant problem in aircraft performance is the presence of turbulent flows over the surfaces of major components such as the aircraft body, wings and engine nacelles. Turbulence significantly increases the overall drag on the aircraft and therefore incurs the penalty of reduced performance and increased fuel demand. A possible solution is to delay the transition from laminar to turbulent flow by applying suction to the surface of the body. In the case of engine nacelles it is desirable to fix the transition at some point. In this paper the optimisation of the flow rates and panel positions is described for a desired transition position. This leads to a nonlinear constrained optimisation problem for which genetic algorithms are used. Results demonstrate that good, low flow rate, solutions can be found for a range of desired transition positions.