三棱柱的低雷诺数绕流研究

Low-Reynolds-number wake flows of a triangular prism

数值模拟了截面为等腰三角形的棱柱在不可压牛顿流体中的二维绕流问题,分析了不同的截面尺度比以及三角形顶点迎风和背风安置时的尾流稳定性与阻力系数.研究发现对于较大截面尺度比的棱柱,在相同雷诺数的情况下顶点迎风相较于顶点背风的情况更易失稳从而产生侧向力,但阻力系数相对较小,当雷诺数为160时,最多能够减少19.4%.进一步地对比研究了顶点迎风与顶点背风在不同截面尺度比时升、阻力系数及涡脱落频率随雷诺数的变化关系.

The two-dimensional incompressible Newtonian flows passing an isosceles tri-angular prism were numerically investigated at low Reynolds numbers, which were defined with the base length. Two geometrical orientations of the prism were used the upwind arrangement （apex facing the flow） and the backwind arrangement （base facing the flow）. This revealed that for large aspect ratio of the cross section, the upwind arrangement was prone to be unsteady than the backwind arrangement at the same Reynolds numbers, hence suffering transverse force but with relatively smaller drag coefficient which can be reduced by at most 19.4% when Reynolds numbers was 160. In addition, the Reynolds number effects on the lift coefficient, drag coefficient and vortex-shedding frequency of the prism at different aspect ratios were discussed for the two arrangements as well.