合成射流控制鼓包分离流动的数值模拟

摘要

为了研究合成射流控制鼓包背风面分离流动的效果,采用商用流体力学软件FLUENT 6.3求解Reynolds平均Navier-Stokes方程,通过分析鼓包壁面摩擦力系数分布、旋涡脱落结构以及射流孔口附近流动结构,揭示了合成射流对分离点不固定的流动分离的控制机理.结果表明：在分离点前施加合成射流可有效缩小回流区范围,涡脱落被施加的激励＂锁定＂,涡脱落的频率等于合成射流的频率.此外,在本研究所考虑的情况下,动量系数越大,控制效果越好.从时均效果看,当施加最大吹气动量系数为0.3691%的合成射流时,分离泡长度减小了11%.%Numerical simulation on the separation flow control over a bump was carried out with synthetic jet actuator before the separation point.The Reynolds averaged Navier-Stocks equations were solved by FLUENT6.3.The mechanism of synthetic jet actuator flow separation control was discussed by analyzing the friction coefficient,the vortex structure separated from the bump and the flow field near the actuator orifice.When the synthetic jet actuator was turned on,the length of the recirculation region can be reduced,and the separation of flow was locked by synthetic jet,so the frequency of separation was equal to the frequency of synthetic jet.For the fixed actuating frequency,the larger the blowing momentum coefficients of the synthetic jet,the shorter the separation region downstream of the bump.When the maximum blowing momentum coefficient is 0.369 1%,the length of separation region can be reduced by 11%.