Large Eddy Simulation of Plasma-Based Control Strategies for Bluff Body Flow

Large eddy simulation was used to explore plasma-based control strategies for the flow past a circular cylinder in crossflow at a Reynolds number of 10,000. Solutions were obtained to the Navier-Stokes equations, using a simple phenomenological model to represent plasma-induced body forces imparted by actuators on the surrounding fluid. The numerical method used a high-fidelity time-implicit scheme, and an overset grid approach. Two fundamentally different control strategies were investigated, consisting of larger actuators that produced a wall-jet-like flow, and smaller actuators that perturbed the unstable shear layers near the separation location. The larger actuators achieved control via a Coanda effect, and were operated both continuously and in a pulsed manner. For pulsed cases, two different bistable states with nonzero time-mean lift were identified. All control cases resulted in at least a 50% decrease in drag, as well as elimination of oscillatory lift. Comparison is made with available experimental data for the baseline case where no control was enforced. Features of the control flowfields are described, and resultant solutions are compared with each other.