A Nonlinear Dynamical Modeling and Control Method for the Vorticity Control of the Flow past a Circular Cylinder

Abstract

Abstract-In this paper a systematic approach for the nonlinear modeling and feedback control of vorticity behind an immersed circular cylinder system was developed. In this technique first a number of control input points over the cylinder and some measurement points for vorticity past the cylinder are assigned. A type of nonlinear dynamic model (namely a Hammerstein-Wiener (HW) model) of the flow field is estimated via system identification techniques using measurement data obtained from a chirp input function. Once the dynamical model of the system is estimated, a controller for the linear block of the HW model is designed using internal model control method, and this controller is then mapped to the HW model by reversing the input/output nonlinearity functions. The procedure described is implemented and tested numerically in MATLAB and CFD computations performed on the closed-loop system show that the controller is capable of achieving significant reduction in the vorticity levels past the cylinder.Index Terms-Flow past a circular cylinder, nonlinear dynamical modeling and control, system identification, hammerstein-wiener method, vorticity control.

Data-driven control of discrete-phase concentration in a vortex involved two-phase flow with optimized energy consumption

“…In addition, non-linear dynamic models were also applied for flow control problems. For instance, an HW model was estimated by Karaca et al [111] for vorticity control past a circular cylinder, in which a PID controller was then designed with good controlling performance. The vortices dynamics was translated to orbit model with lower order for the convince of the turbulence reduce control for a cross-flow plane [94].…”