The structure and dynamics of bubble-type vortex breakdown
The structure and dynamics of bubble-type vortex breakdown
复制标题
气泡型涡流破裂的结构与动力学
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
R. Ash
中科院分区：
文献类型：
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作者：
R. Spall;T. Gatski;R. Ash
本文采用一种独特的非定常、三维、不可压缩流的Navier-Stokes方程离散形式来数值研究旋涡破裂。在计算区域的中轴线上沿着引入Burgers型涡，并允许其在空间和时间上演化。通过改变涡的强度和自由流轴向速度分布，使用以前开发的Rossby数准则作为指导，控制涡破裂区域的位置和大小。虽然涡流破裂气泡的边界似乎是名义上对称的，但内部流场不是。因此，维持气泡区域所需的混合和夹带机制与早期轴对称模型所建议的机制不同。在这项研究中提出的结果，雷诺数为200，是在较高的雷诺数的实验观察，并提出了各种各样的图，以帮助阐明流体物理的定性一致。
A unique discrete form of the Navier-Stokes equations for unsteady, three-dimensional, incompressible flow has been used to study vortex breakdown numerically. A Burgers-type vortex was introduced along the central axis of the computational domain, and allowed to evolve in space and time. By varying the strength of the vortex and the free stream axial velocity distribution, using a previously developed Rossby number criterion as a guide, the location and size of the vortex breakdown region was controlled. While the boundaries of the vortex breakdown bubble appear to be nominally symmetric, the internal flow field is not. Consequently, the mechanisms for mixing and entrainment required to sustain the bubble region are different from those suggested by earlier axisymmetric models. Results presented in this study, for a Reynolds number of 200, are in good qualitative agreement with higher Reynolds number experimental observations, and a variety of plots have been presented to help illuminate the fluid physics.