利用PIV(Particle image velocimetry)光学测量系统,在雷诺数分别为7767和11650时,实验研究了磁场对绕流圆柱的自由表面流动的影响.实验研究结果表明,磁场使边界层内的无量纲平均速度分布偏离对数分布,尾迹变窄变短,分离点向后移;当雷诺数增加到11650时,在相同磁场强度作用下,磁场的影响减弱,从而使边界层内的无量纲平均速度分布偏离对数分布的程度减小.
The effects of magnetic field on the free surface flow around a cylinder were investigated experimentally using the PIV (particle image velocimetry) under Reynolds number 7 767 and 11 650. The experimental result revealed that the field enabled the distribution of nondimensional average velocity to deviate from logarithmic distribution of nondimensional average velocity in the boundary layer, and also made the wake become narrower and shorter, and the detachment point move backward. When the Reynolds's number reached up to 11 650, the influence of magnetic field was weaken under same strength of external magnetic field. Consequently, the departure degree between the nondimensional average velocity distribution and logarithmic distribution in the boundary layer was reduced.