摘要
在雷诺数Re=200的情况,利用Maxwell方程直接数值计算表面包覆电极与磁极圆柱体产生的电磁力分布,将其加入到动量方程中,在各种电磁力作用参数和电磁极宽度的组合下,对表面覆盖电磁极圆柱体在弱电解质中的绕流场结构及其升阻力特性进行了数值模拟与分析.结果表明,当电磁极宽度较小时,圆柱体绕流场的分离点越容易接近后驻点,而电磁力对总阻力的影响并不明显,但对压差和摩擦阻力均有明显影响.当电磁极宽度较大时,圆柱体尾部区域越容易产生射流现象,而且总阻力随电磁力作用参数和电磁极宽度增大而减小.在电磁力尚不足以完全抑制周期性涡脱落的情况下,升力幅值随电磁力作用参数增大而减小,但随电磁极宽度则先减小后略有增加,升力脉动频率则均随电磁力作用参数和电磁极宽度增大而增加.研究表明,电磁力可以有效地改善圆柱体绕流场结构,达到减小圆柱体阻力并抑制其脉动升力之目的,因此是圆柱型结构的一种有效流动控制手段.
The distribution of the electromagnetic force around a cylinder covered by electromagnetic actuators is obtained firstly by solving Maxwell equation system,and then such a Lorentz force is added to the momentum equation of flow governing equation system.The numerical simulation is carried out to simulate and analyze the flow structures around a circular cylinder and its lift/drag characteristics in a weakly conductive fluid under various combinations for electromagnetic interaction parameters and electromagnetic actuator widths when the Reynolds number Re = 200.The results show that for the case of small electromagnetic actuator width,the separation point of the flow around a cricular cylinder is easier close to the back stagnation point,and the electromagnetic force has small influence on the total drag,but it has obvious influence on the pressure and friction.For the case of large electromagnetic actuator width,the cylinder wake is easier to become jet flow,and the total drag decreases as the electromagnetic interaction parameter and the electromagnetic actuator width increase.Moreover,for the case where the electromagnetic force is insuffcient to completely inhibit periodic vortex shedding,the lift amplitude decreases as the electromagnetic interaction parameter increases,but it first has an obvious reduction and then a slight increase as the electromagnetic actuator width increases,and the lift pulsation frequency increases as electromagnetic interaction parameter and the electromagnetic actuator width increase.The results imply that the electromagnetic force can effectively improve the flow structure around a cricular cylinder to achieve the purpose of reducing the drag and inhibiting the lift fluctuation,therefore the flow structures can be improved effectively by the electromagnetic force.
出处
《力学学报》
EI
CSCD
北大核心
2013年第4期493-506,共14页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然学科基金(11272211)
海洋工程国家重点实验室基金(GP010819)资助项目~~
关键词
圆柱绕流
流动控制
电磁力
数值模拟
flow around a circular cylinder
flow control
electromagnetic force
numerical simulation
作者简介
尤云祥，教授，主要研究方向：船舶与海洋工程水动力学．E-mail：youyx@sjtu．edu．cn
