Flow Control of Transonic Airfoils using Optimum Suction and Injection Parameters

In this paper, the application of the surface mass transfer optimization in shock wave-boundary layer interaction control at off-design conditions of transonic aircraft wing is presented. The suction or injection parameters include for example its position on the airfoil, its angle, the length of the hole and the rate of the injected or sucked flow. The optimization process is carried out using an efficient Genetic Algorithm (GA) method. The compressible viscous flow equations in Reynolds Averaged form are solved together with a twoequation k-epsilon turbulence model to accurately compute the objective function. Four different objective functions are introduced including maximum lift to drag ratio, minimum drag coefficient, maximum lift to drag ratio with no drag increment and minimum drag coefficient with no lift decrement. Effectiveness of each objective function is examined by comparing the optimum results in terms of the flow control parameters and flow characteristics.