剪切来流下电磁减阻与尾流控制  

Drag Reduction and Wake Flow Control by Lorentz Force in Shear Flow

作　　者：张辉[1] 范宝春[1] 贺旺[1] 李鸿志[1] 

机构地区：[1]南京理工大学瞬态物理重点实验室,江苏南京210094

出　　处：《兵工学报》2010年第10期1285-1290,共6页Acta Armamentarii

摘　　要：电解质溶液中圆柱表面附近分布的电磁力可有效改变圆柱流体边界层,控制圆柱绕流。对剪切来流情形下圆柱绕流及其电磁控制进行了实验和计算研究。实验在转动水槽中进行,通过吊杆将装有电磁激活板的圆柱插在槽内液体中。吊杆上的应变片用于测试圆柱的阻力,注入适当的染料用来显示流场。数值模拟时,流场的基本方程为指数极坐标中考虑场力的Navier-Stokes方程,计算采用交替方向隐式格式和快速傅里叶变换格式。研究结果表明:剪切来流的绕流流场中,圆柱的尾涡向流速小的一侧偏移,升力和阻力周期性振荡,且升力的均值不为0,指向流速较小的一侧;电磁力作用后,圆柱的尾迹呈一条线向流速较小的一侧偏移,阻力减小且不再振荡,升力增大至稳定,指向流速较小的一侧。The boundary layer flow of cylinder can be modified effectively by Lorentz force near the surface of the cylinder in the weakly conductive fluid which holds the advantages for cylinder wake control.The experiment and calculation of cylinder wake and its electromagnetic control were investigated in the shear flow.Experiments were conducted in a rotating annular tank filled with a low-conducting electrolyte.A cylinder with electromagnetic actuators mounted on the surface was placed into the electrolyte.Force measurements were carried out by strain gages attached to a fixed beam to which the cylinder was suspended and flow fields were visualized by dye markers.Based on the Navier-Stokes equations considering the electromagnetic body force,i.e.Lorentz force,in the exponential-polar coordinates,the numerical investigations were carried out by means of an alternative-direction implicit alogorithm and a fast Fourier transform algorithm.The experimental and calculated results show that the cylinder wake leans towards the side of slow velocity of flow.The drag and lift vary periodically.The average value of lift is not 0 any longer,and its direction points to the side of slow velocity of flow.The wake becomes a line leaning to the side of slow velocity of flow under the action of Lorentz force.The drag decreases and doesn＇t oscillate any longer.The lift increases and turns to steady which points to the side of slow velocity of flow.

关 键 词：流体力学 剪切来流 流体控制 圆柱绕流 

分 类 号：O361[理学—流体力学]