Third Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP3
Opposition Control of Near-wall Turbulence - A Real-time Experiment
pages 173-178
DOI: 10.1615/TSFP3.300
摘要
Recent DNS studies have shown that the near-wall turbulence can be controlled with a simple control scheme, providing up to 25% skin-friction drag reduction. Opposition control establishes a 'virtual wall', a plane with effectively no through flow, preventing a downwash of high-momentum fluid towards the wall during the sweep events. In this paper, we report recent experimental results where opposition control was carried out in real time using wall-normal jet from an actuator. By improving on the detection technique and the actuator used, we were able to selectively cancel the downwash of high-momentum fluid in the near-wall region of the turbulent boundary layer.