Vortex-Induced Stall on an Actively Twisted Highly Loaded Model Rotor Blade

Abstract

In preparation for a future wind tunnel test of a rotor with twist-actuated blades (STAR II), numerical predictions of this test have been carried out by the contributing partners. In this paper, the simulated results of the vortex-induced stall operating condition, synonymous with a highly loaded flight condition, are presented. The current conclusion is that a noticeable spread of the results is given when searching for the maximum attainable thrust, depending on the onset of stall once perceived by the individual simulation methodology. Some general trends among the simulations could still be identified with respect to the actuation settings that reduce vibrations and the required power. Generally, most CFD-based results allowed to capture this physical phenomenon, but carefully tuned low-fidelity aerodynamic tools also managed to capture the same trends at a fraction of the computational cost.