Active Flow Control on a High-Lift Airfoil: URANS Simulations and Comparison with Time-Accurate Measurements

Kurzfassung

This paper presents a validation of unsteady computational results for active separation control with time-averaged and time-accurate wind tunnel measurements. The selected method to control the flow separation on multi-element airfoils resembles a pulsed blowing with a squared signal at moderate energy requirements. The focus is on controlling a large trailing edge flap separation for an overall high-lift enhancement. These studies were performed to show the ca- pability to simulate the complex physical processes and to deliver the possible shortfalls for this numerical method. The studies address double-slot actuators and corresponding three-dimensional simulations are performed. The approach is based on solving the Reynolds-averaged Navier-Stokes equations for modeling time-dependent physical problems with the objective to explore the relevant mean and unsteady aerodynamic characteristics for (state of the art) high-lift airfoils with flow control. The computed aerodynamic lift coecients, sectional pressure distributions and time-resolved flowfield visualizations are compared with wind tunnel experiments. In general, a good agreement is observed that underlines the applicability of this numerical method for unsteady flow control applications. Two state of the art eddy viscosity turbulence models are used and significant differences in the computed flowfield are reported for the flow control simulation, but not for the baseline.