Swirling-strength based large eddy simulation of turbulent flowaround single square cylinder at low Reynolds numbers∗
Swirling-strength based large eddy simulation of turbulent flowaround single square cylinder at low Reynolds numbers∗
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基于旋流强度的低雷诺数下单个方形圆柱体周围湍流的大涡模拟
DOI：
10.1007/s10483-014-1847-7
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Li Yinglin
中科院分区：
文献类型：
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作者：
Zhu Zuojin;Niu Jianlei;Li Yinglin
鉴于大尺度涡旋在大气中起着重要的作用。湍流中的动量输运，大涡模拟（LES）被认为是。一个更好的仿真模型。然而，亚网格尺度（SGS）模型迄今为止报道较少。还没有确定在什么流动条件下LES可以进入直接的数值模拟。为了克服这种差异，本文开发了一个旋流强度。基于SGS模型对湍流间歇性进行了适当的模拟，并采用了初级模型。当局部旋流强度为零时，局部亚栅粘度为零。将会消失。本文采用该模型对其流动特性进行了研究。零入射不可压缩湍流绕单方圆柱体（SC）流动。在低雷诺数范围Re∈[103,104]。研究了流动特性。包括雷诺数对升力和阻力系数的依赖关系、分布。的时间跨度平均变量，如子网格粘度和对数。柯尔莫哥洛夫微尺以10为基底，在Re = 2 500和104处，等高线向跨度。以及t = 170时的顺流涡度分量。的峰值。亚栅粘度比及其均方根值随雷诺数的增大而增大。湍流动能耗散速率在SC固体壁面附近较大，瞬时旋流强度间歇性因子（FSI）表现出一定的层状。与漩涡脱落有关的结构。
In view of the fact that large scale vortices play the substantial role of.momentum transport in turbulent flows, large eddy simulation (LES) is considered as.a better simulation model. However, the sub-grid scale (SGS) models reported so far.have not ascertained under what flow conditions the LES can lapse into the direct numerical.simulation. To overcome this discrepancy, this paper develops a swirling strength.based the SGS model to properly model the turbulence intermittency, with the primary.characteristics that when the local swirling strength is zero, the local sub-grid viscosity.will be vanished. In this paper, the model is used to investigate the flow characteristics.of zero-incident incompressible turbulent flows around a single square cylinder (SC).at a low Reynolds number range Re ∈ [103, 104]. The flow characteristics investigated.include the Reynolds number dependence of lift and drag coefficients, the distributions.of time-spanwise averaged variables such as the sub-grid viscosity and the logarithm of.Kolmogorov micro-scale to the base of 10 at Re = 2 500 and 104, the contours of spanwise.and streamwise vorticity components at t = 170. It is revealed that the peak value of.sub-grid viscosity ratio and its root mean square (RMS) values grow with the Reynolds.number. The dissipation rate of turbulent kinetic energy is larger near the SC solid walls..The instantaneous factor of swirling strength intermittency (FSI) exhibits some laminated.structure involved with vortex shedding.