The decay of axisymmetric homogeneous turbulence
The decay of axisymmetric homogeneous turbulence
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轴对称均匀湍流的衰减
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
J. Chasnov
中科院分区：
文献类型：
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作者：
J. Chasnov
通过大涡模拟研究了由作用在初始时刻的轴对称分布的随机脉冲力产生的均匀湍流的衰减。冲击力可以平行或垂直于对称轴。对于导致湍流的k4低波数能谱的脉冲力，只要雷诺数大，则确定在长时间内所有运动尺度上的流接近各向同性。然而，对于最初由Saffman [J. Fluid Mech.27，581（1967）]提出的冲击力类型，其中产生k2低波数能谱，湍流仅在最小尺度下接近各向同性，并且在最大和含能量尺度下保持显著的各向异性。然而，流场的相似状态是渐近建立的，其中湍流的每单位质量的动能衰减为t-6/5。
The decay of a homogeneous turbulence generated by an axisymmetric distribution of random impulsive forces acting at the initial instant is studied by means of large‐eddy simulations. The impulsive forces may be either parallel or perpendicular to the symmetry axis. For impulsive forces, which result in a k4 low wave number energy spectrum of the turbulence, it is determined that the flow approaches isotropy on all scales of motion at long times, provided the Reynolds number is large. However, for the type of impulsive forces originally proposed by Saffman [J. Fluid Mech. 27, 581 (1967)], in which a k2 low wave number energy spectrum is produced, the turbulence approaches isotropy only at the smallest scales, and remains significantly anisotropic at the largest and energy‐containing scales. Nevertheless, a similarity state of the flow field establishes itself asymptotically, in which the kinetic energy per unit mass of the turbulence decays as t−6/5.