亚临界区雷诺数下圆柱绕流场电磁力控制数值研究

在亚临界区雷诺数下,采用脱体涡模拟方法对弱电解质中电磁力作用下圆柱绕流场及其升阻力特性进行了数值模拟与分析。结果表明,电磁力可以提高圆柱体边界层内的流体动能,延缓圆柱体近壁面流动分离,减弱绕流场中流向和展向大尺度涡的强度,减小圆柱体阻力及其升力脉动幅值;当电磁力作用参数大于某个临界值后,流动分离角消失,在圆柱体尾部产生射流现象,电磁力产生净推力作用,出现负阻力现象,而且升力脉动幅值显著减小且接近于零。

Numerical investigation of flow characteristics around a circular cylinder controlled by electromagnetic force at subcritical Reynolds numbers

For subcritical Reynolds numbers, the flow field and drag/lift characters of cylinder wake by the electromagnetic force in a weakly conductive fluid are simulated and analyzed with the Detached Eddy Simulation (DES) method. The results show that the electromagnetic force can increase the kinetic energy near the fluid boundary layer of the circular cylinder, delay the flow separation near the surface of cylinder, weaken the scale and intensity of the streamwise and spanwise vortex and decrease the drag force and the fluctuation amplitudes of the lift of the circular cylinder. Moreover, when the interaction parameter of electromagnetic force is larger than some certain critical values, the separation point is suppressed, the jet flow phenomenon is generated behind the circular cylinder, the net thrust effect is generated, and the negative drag occurs. Furthermore, the fluctuation amplitudes of the lift decreases significantly and then tends to approach zero.