Drag reduction by active control for flow past cylinders

摘要: The main objective of this article is to investigate computational methods for the active control and drag optimization incompressible viscous flow past cylinders, using two-dimensional Navier-Stokes equations as model. methodology relies on following ingredients: space discretization by finite element approximations, time a second order accurate two step implicit/explicit difference scheme, calculation cost function gradient adjoint equation approach, minimization quasi-Newton method la BFGS. above have been applied predict optimal forcing-control strategies in reducing around circular cylinder either an oscillatory rotation or blowing suction. In case forcing, reduction 31% at Reynolds number 200 61% 1000 was demonstrated. Using only three blowing-suction slots, we able completely suppress formation Von-Karman vortex street up with significant net reduction. We conclude appendix describing bisection which allows very substantial storage memory savings reasonable extra when applying based methodologies solution problems modeled dependent equations.