平行磁场作用下的低雷诺数平板流研究

Investigation of Plane Channel Flow at Low Reynolds Number Under Parallel Magnetic Field

用直接数值模拟方法,对平行磁场作用下的不可压缩导电流体在两无限大平行平板内的流动特性进行了研究.磁场的取向可以是侧向的(与主流方向垂直),也可以是流向的(与主流方向平行),主要讨论了后一种情况.流向磁场的主要作用是增强流向上的脉动速度,而抑制侧向和法向的脉动速度及动量传输.当施加的流向磁场强度足够大时,流场从湍流转变为层流,而通过施加背景噪声或脉冲噪声的方法不能使流场重新转变为湍流.

In the presence of a parallel magnetic field, the suppression of turbulent tiuctuations m the plane channel filled with incompressible conducting fluids was investigated using direct numerical simulation method. The magnetic orientations concerned were the spanwise and streamwise directions, and the latter one was discussed mainly. The imposed streamwise magnetic field stimulates streamwise velocity fluctuations, while inhibits fluctuations in the other two directions. Relaminarization can be realized when the imposed streamwise magnetic field is sufficiently strong, but the transition from laminar to turbulence can not be observed by imposing three dimensional random background or impulse noises under the streamwise magnetic field.