Discrete Adjoint based Sensitivity Analysis for Optimal Flow Control of a 3D High-Lift Configuration

Active flow control techniques are used to delay or prevent the turbulent flow separation on the flap of a high-lift configuration. Effective separation control and thus lift enhancement can be achieved by finding the optimal set of actuation parameters, which may be in very large number. In this paper, a consistent unsteady discrete adjoint RANS solver in three-dimensions is developed towards the objective of finding the optimal set of actuation parameters. The adjoint code is applied to the sensitivity analysis of a practically relevant three-dimensional high-lift configuration. The sensitivities with respect to actuation parameters based on the consistent adjoint approach are compared with finite differences. The effect of frozen turbulence assumption on the accuracy of actuation sensitivities is studied.