Abstract

Resolvent analysis reveals the harmonic relations between the forcing inputs and response outputs with respect to a base flow.  By combining our understanding of the baseline flow physics and the resolvent mode characteristics, effective and efficient flow control strategies can be developed to alter the time-average flows.  This approach provides us with a physics-driven flow control method, without having to resort to expensive parametric computational and experimental studies.  We also discuss our recent efforts in extending the traditional resolvent analysis to (1) incorporate randomized numerical linear algebra to enable examining higher-Reynolds number turbulent flows; (2) establish a sparsity-promoting formulation to determine the optimal actuator location and the forcing variable; and (3) integrate network broadcast analysis into the resolvent formulation to study time-varying base flows.  In this talk, we demonstrate the use of these resolvent analysis techniques for examples of actively controlling turbulent separated flow over a NACA 0012 airfoil, high-speed open cavity flow, and isotropic turbulence.