Equilibrium similarity, effects of initial conditions and local Reynolds number on the axisymmetric wake
Equilibrium similarity, effects of initial conditions and local Reynolds number on the axisymmetric wake
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DOI：
10.1063/1.1536976
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发表时间：
2003-01
影响因子：
4.6
通讯作者：
P. B. Johansson;W. George;M. Gourlay
中科院分区：
文献类型：
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作者：
P. B. Johansson;W. George;M. Gourlay
平衡相似的考虑被应用于轴对称湍流尾迹，而不是先前理论研究中的任意假设。对于湍流有两种解：一种是无限大的局部雷诺数，其空间增长为x1/3；另一种是小的局部雷诺数，其增长为x1/2。这两种解都可以依赖于上游条件。此外，局部雷诺数随着下游距离的增加而减小，因此即使在初始雷诺数较大的情况下，流动也会从一种状态向另一种状态发展。大多数可用实验数据的初始雷诺数太低和/或测量得太靠近尾迹产生器，不能提供x1/3解的证据。然而，在圆盘尾迹上的实验室实验和直接数值模拟(DNS)的新结果与这一解决方案非常一致，一旦流动有足够大的下游距离来演变。超过这个范围，湍流的比率会增加。
Equilibrium similarity considerations are applied to the axisymmetric turbulent wake, without the arbitrary assumptions of earlier theoretical studies. Two solutions for the turbulent flow are found: one for infinite local Reynolds number which grows spatially as x1/3; and another for small local Reynolds number which grows as x1/2. Both solutions can be dependent on the upstream conditions. Also, the local Reynolds number diminishes with increasing downstream distance, so that even when the initial Reynolds number is large, the flow evolves downstream from one state to the other. Most of the available experimental data are at too low an initial Reynolds number and/or are measured too near the wake generator to provide evidence for the x1/3 solution. New results, however, from a laboratory experiment on a disk wake and direct numerical simulations (DNS) are in excellent agreement with this solution, once the flow has had large enough downstream distance to evolve. Beyond this the ratio of turbulence inten...