电磁激活板的宽度对圆柱绕流控制的影响

电磁力可以改变流体边界层的结构,是控制流体运动的主动控制方法之一。基于电磁场和流体的基本方程,对置于弱电介质中的圆柱电磁激活板周围产生的Lorentz力及其对圆柱绕流的控制进行了数值模拟,着重讨论了电磁激活板的宽度对其周围的电磁场、产生的Lorentz力、流场的控制和涡量变化的影响。电磁场包覆范围为流体分离点至其后部,当N值较小时,分离点后移,但不能够完全抑制流体的分离,极板越宽对尾涡的抑制效果越好;随着N值的增大,由于极板窄的表面涡量大,所以可以首先达到完全抑制流体分离的控制效果;当N值较大时,无论极板宽窄,都可以达到完全抑制流体分离的效果。

CYLINDER WAKE FLOW AFFECTED BY WIDTH OF ELECTOR-MAGNETIC ACTUATOR

Since the structure of flow boundary layer can be modified by the electro-magnetic body forces, one of active control methods might be developed by adjusting the forces so as to control the layer. Based on the equations of magnetic and electric fields and the formula of the flow, the distribution of Lorentz force and its control effect on cylinder wake flow have been investigated numerically in the electro-magnetic fields formed by a moving low-conducting electrolyte. The influences of actuator width to the distribution of electro-magnetic fields, Lorentz force, flow field are simulated and discussed. The electro-magnetic fields are covered from the separation points to the end of cylinder. While the interaction parameter N is small, the separation points on the cylinder surface will be moved rearward, but it can not be suppressed completely. In this case, our simulated results show the better control effect. With the increase of N reaching to the critical value, since the narrow actuator has a large surface vortex, its suppressing effect for flow separation is prominent. When Nbecomes large, the separation points can be suppressed completely, and the suppression effect is independent of the actuator width.