亚临界区雷诺数下电磁力控制圆柱绕流场特性研究

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。研究结果表明，在亚临界区雷诺数下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。

Flows Around a Circular Cylinder Controlled by Electromagnetic Force at Subcritical Reynolds Numbers

This paper numerically researches the flow structures around a circular cylinder and the lift/drag characteristics influenced by the electromagnetic force in a weakly conductive fluid at sub-critical Reynolds numbers with the method of Detached Eddy Simulation (DES). The results show that the electromagnetic force can increase the kinetic energy near the boundary layer of the circular cylinder, delay the flow separation near the cylinder wall, weaken the intensity of the streamwise and spanwise vortexes and decrease the drag force and the fluctuation amplitudes of the lift. Moreover, as the electromagnetic force parameter N exceeds a certain critical value, at which the separation point disappears, the flow behind the circular cylinder behaves like a jet, which generates a net thrust ef-fect and implies the existence of negative drag phenomenon, while the fluctuation amplitudes of the lift are significantly reduced and close to zero.