Third Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP3
TURBULENT FRICTION-DRAG REDUCTION CONTROL-SCHEME REQUIRING ONLY STREAMWISE WALL SHEAR SIGNAL
pages 157-162
DOI: 10.1615/TSFP3.270
ABSTRAKT
We propose a new algebraic control scheme for drag reduction in wall-turbulence, which requires the streamwise wall-shear signal only. By assuming continuously distributed sensors and actuators, the controller is designed to reduce the near-wall Reynolds shear stress that is directly responsible for the turbulent skin friction drag. Intuitive and suboptimal control schemes are considered. The derived control laws are assessed by means of direct numerical simulation of turbulent pipe flow at Reτ ~ 180. A clear drag reduction symptom associated with a negative near-wall Reynolds stress is observed when the control scheme derived by the suboptimal control theory is applied.