ACTIVE FLOW CONTROL OF WAVY CYLINDER BASED ON STEADY BLOWING AND SUCTION

Based on the control of the near wake flow of a wavy cylinder by steady blowing and suction to enhance the vibration of the cylinder, the effects of the forward blowing and backward suction and the forward and backward suction control modes on the lift and drag characteristics, time-average pressure coefficient, circulation, turbulent kinetic energy and flow field mechanism of a wavy cylinder under different blowing and suction conditions at subcritical Reynolds number (Re = 3000) were numerically studied by large eddy simulation. It is found that the fluctuating lift coefficient of wavy cylinder under the control of forward blowing and backward suction and forward and backward suction is significantly increased under different conditions of blowing and suction momentum coefficient, and the maximum increase is as high as 636% and 391% respectively compared with that of uncontrolled cylinder and wavy cylinder. This may be mainly attributed to the shorter recirculation area of wavy cylinder under the control of blowing and suction, the concentration of high-intensity vortices towards the rear of blunt body, and the shorter vortex formation length, The "riblike vortex" formed by the interaction of spanwise vortex and streamwise vortex becomes larger and longer, and the normalized circulation near the wake increases significantly, resulting in the increase of fluctuating lift coefficient, which may lead to stronger vibration of the cylinder; At the same time, both control methods change the pressure distribution on the surface of the wavy cylinder. Because the front end tends to be streamlined due to the blowing at the front stagnation point of the wavy cylinder, the high-pressure area of the wavy cylinder decreases under different blowing and suction momentum coefficients, but the low-pressure area increases due to the suction at the rear stagnation point, while the high-pressure area of the wavy cylinder is basically unchanged and the low-pressure area increases under different blowing and suction momentum coefficients. The research results can provide basic theoretical support for improving the efficiency of distributed wind energy capture structure in low wind speed areas.