Wasim Sarwar
Polytechnic University of Catalonia, Spain
Title: Numerical investigation of fluidic active flow control on circular cylinder in transitional regime
Biography
Biography: Wasim Sarwar
Abstract
The fluid flow past bluff bodies even in the low to moderate regimes results in large unsteady wakes that are the source of high aerodynamic drag, vibration, noise etc. Most applications aim at the reduction of the drag force and vibrations to improve aerodynamic performance, while an enhancement of the wake instability can be beneficial for energy harvesting applications. In the present numerical study, we apply spanwise-dependent fluidic actuation, both steady and time-periodic, on the flow past a circular cylinder at Reynolds number 2000. The actuation takes the form of in-phase blowing and suction from slits located at ±90º (top and bottom) with respect to the upstream stagnation point. Optimal forcing amplitude and wavelength are obtained by sweeping across the parametric space. A promising reduction in drag force, combined with the suppression of lift fluctuations, is obtained for spanwise-dependent steady actuation with appropriate actuation wavelength. Several actuation frequencies are investigated for time-dependent actuation. Lift fluctuations and drag force are found to increase significantly under actuation at frequencies close to the shear layer instability, thus indicating a potential interest for energy harvesting applications at these low Reynolds numbers.