Quantitative properties of oscillating-grid turbulence in a homogeneous fluid
Quantitative properties of oscillating-grid turbulence in a homogeneous fluid
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均匀流体中振荡网格湍流的定量特性
DOI：
10.1016/s0169-5983(98)00034-3
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发表时间：
1999
影响因子：
1.5
通讯作者：
Akira Masuda
中科院分区：
文献类型：
--
作者：
Nobuhiro Matsunaga;Y. Sugihara;Toshimitsu Komatsu;Akira Masuda
均质流体中的振荡网格湍流处于湍流能量扩散和能量耗散率的平衡状态。用k-epsilon湍流模型对这种场进行了实验研究和分析。在方形网格的垂直振动下，测量了波动速度的垂直分量和水平分量。通过测量得到了湍流能量k、耗散率epsilon、垂直能量通量F、涡流粘度ν t和纵向尺度l t五个特征量的垂直分布。在模型分析中，采用栅格振荡中心虚拟给出的湍流能量k 0和耗散率epsilon 0作为边界条件，对控制方程和边界条件进行了无量纲化处理。导出了k、F、ν t和l t的无因次解析解。实验数据表明，解析解之间存在一定的联系。这表明k-epsilon模型在振荡网格湍流中的应用是有效的。解析解包括三个模型参数。它们的值是由实验数据确定的。k0和epsilon 0的值通过将k、epsilon和F的解析解叠加在它们的实验数据上来计算，并与实验参数进行了经验关联。利用k0和ε 0的经验关系和解析解，我们可以估计振荡网格湍流的k、ε、F、ν t和l t。
Oscillating-grid turbulence in a homogeneous fluid is in equilibrium between the diffusion of turbulent energy and the dissipation rate of the energy. Such a field has been investigated experimentally and analyzed by using the k–epsilon turbulence model. Vertical and horizontal components of fluctuating velocity have been measured under the vertical oscillation of a square grid. Vertical profiles of five characteristic quantities, the turbulent energy k, the dissipation rate epsilon, the vertical energy flux F, the eddy viscosity ν t and a lengthscale l t, have been obtained from the measurements. In the model analysis, the governing equations and the boundary conditions have been non-dimensionalized by using the turbulent energy k 0 and the dissipation rate epsilon 0 which are given virtually at the center of the grid oscillation as boundary conditions. Dimensionless analytical solutions of k, epsilon, F, ν t and l t have been derived. The experimental data show some relationships existing between the analytical solutions. This shows the application of the k–epsilon model to the oscillating-grid turbulence to be valid. The analytical solutions include three model parameters. Their values have been determined from the experimental data. The values of k 0 and epsilon 0 have been evaluated by superposing the analytical solutions of k, epsilon and F on their experimental data, and have been related empirically to the experimental parameters. Using the empirical relations for k 0 and epsilon 0 and the analytical solutions, we can estimate k, epsilon, F, ν t and l t of the oscillating-grid turbulence.