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本文数值模拟雷诺数Re=100的条件下,脉动流振幅和频率分别为0.2≤A≤0.8和0≤f_P≤20 Hz时方柱绕流特性.通过数值计算得到方柱绕流的升、阻力系数,涡脱频率及尾涡特性,且稳定流下计算结果与文献结果一致。研究结果表明脉动流是一种有效的主动流动控制方法;在脉动流频率f_P为1.2~2.6自然涡脱频率f_(sn)时,旋涡脱落频率存在“锁定”现象;在锁定范围内,尾涡形成区域变短,时均阻力系数显著增大,且在脉动流频率等于两倍频率时,时均阻力系数达到峰值;随着振幅的增大,频率“锁定”范围增大。
In this paper, the numerical simulation of Reynolds number Re = 100 under the conditions of the pulsatile flow amplitude and frequency of 0.2 ≤ A ≤ 0.8 and 0 ≤ f_P ≤ 20 Hz when the square column flow characteristics of the square column flow through the rise and resistance Coefficient, eddy frequency and trailing vortex characteristics, and the steady flow calculation results are consistent with the literature. The results show that the pulsating flow is an effective active flow control method. When the pulsating flow frequency f_P is 1.2 ~ 2.6 natural vortex frequency f_ (sn), the vortex shedding frequency has a “locking” phenomenon. Within the locking range, The vortex formation area becomes shorter and the average drag coefficient increases significantly. When the frequency of the pulsating flow equals twice the frequency, the average drag coefficient reaches the peak value. With the increase of the amplitude, the range of frequency “lock” increases.