The Wake Of Rotating Oscillating Rectangular Cylinder With B/H=5

Most studies focus on the static or with small angle of attack rectangular prism of chord to thickness ratio B/H=5,while there are few studies on the wake structure of rotary rectangular plate.Therefore,under the conditions of Reynolds number Re=1200,amplitude 2.5^o～15^o and dimensionless vibration frequency f_eH/V_∞=0.01～0.11,the wake vortex structure of two-dimensional forced oscillation plate is investigated by numerical simulation and experiment,where f_e,H and V_∞are the vibration frequency,thickness and incoming velocity respectively.Five vortex shedding modes（2S,2P,2T,2S₂ and P+S）are observed.The zone of every mode is found out and drawn on the amplitude-reduced frequency plane.Due to the different forms of vortex shedding,the velocity profile presents three shapes:V、W and asymmetric W.By comparing the power spectrum of velocity profile and the root mean square value of aerodynamic coefficient,the effects of amplitude and vibration frequency on wake vortex energy and aerodynamic characteristics are explored,and higher harmonics are found in the power spectrum.In the flutter analysis of rectangular plates,it is found that when f_eH/V_∞is less than 0.04,Scanlan’s linear expression is no longer applicable,while when 0.04<f_eH/V_∞<0.11,the flutter derivative is a linear function of dimensionless vibration frequency and does not change with the change of amplitude.The vorticity field,velocity field and flutter derivative obtained from the experiment are compared with the results of numerical simulation Under specific working conditions,which further verifies the ability of k-εreliable model to predict the flow field of rectangular plate of B/H=5.