Progress toward closed loop control of a flow around an airfoil with coanda blowing

Abstract

Progress toward developing a closed loop control of flow around an airfoil with a Coanda flap is presented. Two loop components were addressed and analysed for the reference no-blowing case: the estimator and its input signal. For the estimator, a Proper Orthogonal Decomposition (POD) Galerkin model based on unsteady Reynolds averaged Navier-Stocks (uRANS) data was evaluated. To compensate for the unresolved dissipative scales in uRANS and for truncation error, the POD Galerkin model was calibrated by introducing an eddy viscosity term. The calibrated POD Galerkin model succeeded in replicating the time coefficients of the first two modes but failed to replicate the higher modes. The sensor location over the flap was optimized using modified Linear Stochastic Estimation (mLSE). With an optimal sensor placement it was possible to determine the state of the flow more accurately than for the same number of evenly spaced sensors.