Experimental Investigation and Large-Eddy Simulation of the Turbulent Flow past a Smooth and Rigid Hemisphere
Experimental Investigation and Large-Eddy Simulation of the Turbulent Flow past a Smooth and Rigid Hemisphere
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DOI：
10.1007/s10494-015-9690-5
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发表时间：
2016-07-01
影响因子：
2.4
通讯作者：
Breuer, Michael
中科院分区：
文献类型：
--
作者：
Wood, Jens Nikolas;De Nayer, Guillaume;Breuer, Michael
本文的目的是提供一个详细的实验和数值研究的湍流通过半球形障碍物（直径D）。为此目的，海崖体暴露于在Re = 50，000时厚度δ = D/2的厚湍流边界层。在实验中，这个边界层厚度是通过在风洞上游区域放置特定的栅栏来实现的。通过激光多普勒和热膜探头对上游流动条件进行详细测量，可以使用合成湍流流入发生器模拟流场互补大涡模拟的流入条件。这些明确定义的边界和操作条件是流场的实验和数值研究相结合的先决条件，依赖于激光多普勒风速仪和有限体积Navier-Stokes求解器块结构的曲线网格。结果包括在半球附近观察到的非定常流动特征的分析，以及时间平均流场的详细讨论。后者包括平均速度场以及雷诺应力。由于对来流的正确描述和补充数值研究保证了选择适当的网格和亚网格尺度模型，测量结果和预测结果非常吻合。
The objective of the present paper is to provide a detailed experimental and numerical investigation on the turbulent flow past a hemispherical obstacle (diameter D). For this purpose, the bluff body is exposed to a thick turbulent boundary layer of the thickness delta = D/2 at Re = 50,000. In the experiment this boundary layer thickness is achieved by specific fences placed in the upstream region of the wind tunnel. A detailed measurement of the upstream flow conditions by laser-Doppler and hot-film probes allows to mimic the inflow conditions for the complementary large-eddy simulation of the flow field using a synthetic turbulence inflow generator. These clearly defined boundary and operating conditions are the prerequisites for a combined experimental and numerical investigation of the flow field relying on the laser-Doppler anemometry and a finite-volume Navier-Stokes solver for block-structured curvilinear grids. The results comprise an analysis on the unsteady flow features observed in the vicinity of the hemisphere as well as a detailed discussion of the time-averaged flow field. The latter includes the mean velocity field as well as the Reynolds stresses. Owing to the proper description of the oncoming flow and supplementary numerical studies guaranteeing the choice of an appropriate grid and subgrid-scale model, the results of the measurements and the prediction are found to be in close agreement.