Large-eddy simulation-based characterization of suction and oscillatory blowing fluidic actuator

Unsteady turbulent flows inside a suction and oscillatory blowing actuator are simulated and characterized to provide better physical understanding of the complex actuator flows. Large-eddy simulation based upon a novel unstructured-grid technique is used to accurately calculate turbulent flows inside the actuator operating in still air. Simulations are performed for three inlet pressure conditions. Results show good agreement with the corresponding experimental measurements. The actuator is characterized by parameters such as pressure ratio, outlet velocity profile, oscillation frequency, and suction-to-total flow rates. The large-eddy simulation-generated data are used to develop a reduced-order model applicable to integrated simulation of aerodynamic flow control as an unsteady boundary condition. Dynamic mode decompositionis employed to obtain a lower-order representation of streamwise velocity at the actuator outlets. The frequency-optimized characteristics of dynamic mode decomposition enables to compactly represent the oscillatory turbulent outflows. Using the sparsity-promoting algorithm, an optimal representation of the actuator outflows is systematically derived. Using only two distinct dynamic modes, the sparsity-promoting variant of the standard dynamic mode decomposition algorithm adequately describes unsteady velocity fields at the actuator outlets.