旋转圆柱层流绕流出现二次不稳定现象的数值模拟  

Numerical Simulation About the Second Instability in the Two-Dimensional Laminar Flow Past a Rotating Circular Cylinder

作　　者：王丹[1] 于勇[1] 

机构地区：[1]北京理工大学宇航学院,飞行器动力学与控制教育部重点实验室,北京100081

出　　处：《北京理工大学学报》2015年第11期1101-1107,共7页Transactions of Beijing Institute of Technology

基　　金：国家自然科学基金资助项目(10702009)

摘　　要：采用数值模拟方法,计算了旋转圆柱在层流状态下流场随雷诺数和转速的变化.针对旋转圆柱在均匀流中引起的涡脱落以及二次不稳定现象,进行了分析.选取雷诺数为Re=60,80,100,130,160,240时,将圆柱的转速一直增大,直到流场第二次达到稳定状态.比较了圆柱的旋转在流场达到第一次及第二次不稳定状态时对其表面的气动力、涡量以及周围流场影响的不同.计算结果表明,低转速下,流场出现初次不稳定状态时,雷诺数为Re=60,80,100,130,160,240,所对应的临界转速比分别为α=1.40,1.70,1.80,1.85,1.90,1.95;随着转速的升高,流场再次出现不稳定状态,所对应的转速比区间分别为5.1<α<5.6,4.9<α<5.4,4.6<α<5.2,4.4<α<5.0,4.3<α<4.9,4.2<α<4.7.A numerical simulation method was taken to simulate the state that the flow was changing with Reynolds number and speed when a rotating circular cylinder was placed in a uniform stream.A comprehensive description was made to analyze the second instability state led by a rotating circular cylinder.The Reynolds numbers were set as Re=60,80,100,130,160,240 with an increasing rotational speed until the flow was stable again.The different effect was analyzed and compared for the aerodynamic forces on the surface of cylinder,vorticity and the flow field around the cylinder in the first and second region of instability.The results show that when the flow is unstable with low rotational speeds,the critical rotational speeds are respectivelyα=1.40,1.70,1.80,1.85,1.90,1.91 for the Reynolds numbers Re=60,80,100,130,160,240.And in higher rotational speeds,the flow turns into unstable again and the related speed ranges are 5.1〈α〈5.6,4.9〈α〈5.4,4.6〈α〈5.2,4.4〈α〈5.0,4.3〈α〈4.9,4.2〈α〈5.7respectively.

关 键 词：旋转圆柱 二次不稳定 临界转速 升阻力系数 涡量 

分 类 号：O355[理学—流体力学]