Simulated annealing based optimal control for boundary layer transition

This paper reports further work on the design of feedback control schemes for boundary layer transition control, i.e. the use of feedback control laws to delay the transition from laminar to turbulent flow and thereby achieve an overall reduction in the drag force acting on an aircraft. Previous work has shown that this is a feasible problem-both in theory and, more importantly, in practice where this conclusion has been reached on the basis of wind tunnel test results for cases with gradient based controllers designed on the basis of a local linear model identified about selected operating points. The local linear model based approach fails to give satisfactory results in cases where such models are not an adequate approximation to the process dynamics. This paper reports new control algorithms designed by using stochastic optimization techniques, specifically simulated annealing, to minimize nonlinear cost functions.