Robust transition control in non-periodic channels

This paper presents the controller synthesis of a network of local robust controllers for the purpose of controlling the transition from laminar to turbulent flow in non-periodic channels, using a recently proposed spatially interconnected model of plane Poiseuille flow for Re = 2000. Measured feedback signals used by the controllers are the local changes in wall shear force, and the generated control action is a local change in fluid wall normal velocities. Thus, in contrast to most previously proposed control schemes which operate in Fourier domain, this approach works in physical domain. In order to synthesize this controller, first uncertainties are estimated by finding the relative error between the measurements obtained from linearized and non-linear models. For this purpose a non-linear simulation environment is developed in FLUENT software. Once these uncertainties are estimated in frequency domain, a low order spatially interconnected weighting function is found. The closed loop response shows that the controller attenuates oscillations generated by an impulsive disturbance.