双柱体绕流中高度变化对其阻力的影响

对三维槽道内双柱体可压绕流进行了大涡模拟,揭示了绕流过程中柱体表面分离涡的生成、扩散与相互作用过程,并且数值模拟了两个柱体高度(阻塞比)的变化对整个流场的影响以及两柱体阻力系数的变化情况。结果表明,当两个柱体高度同时增加时,上游柱体阻力系数的大小以及下游柱体阻力系数的振幅都急剧变大,这是工程领域中所不期望的。而当仅增加下游柱体高度时,上游柱体阻力系数会略有降低,下游柱体阻力系数虽有增加,但仍小于前种情况的上游柱体阻力系数,且其振幅相对较小,因而有利于改善两柱体总体受力情况。

Influences of two-cylinder heights on their drag coefficients in a rectangle channel

Large eddy simulation (LES) of flow past over two wall-mounted rectangle cylinders in a rectangle channel has been performed in this paper. Our numerical results show that the development and interaction processes of vortices shedding from two cylinders,moreover, the variations of two-cylinder drag coefficients with the increase of their height have been calculated. With the increase of two-cylinder heights, both of the drag coefficient value of upstream cylinder and the drag vibration amplitude of the downstream cylinder increase quickly, and these are not desired in engineering field. However, if we just increase the downstream cylinder height, then the upstream cylinder drag coefficient decreases slightly, although the drag coefficient of downstream cylinder increases, but its value is still small compared to the drag coefficient of the upstream cylinder in the first case, in addition, its variation amplitude is also small comparatively. Therefore, the drag forces of both two cylinders have been improved with the increase of downstream cylinder height.