CFD modelling of unsteady cross ventilation flows using LES
CFD modelling of unsteady cross ventilation flows using LES
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DOI：
10.1016/j.jweia.2008.02.031
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发表时间：
2008-10-01
影响因子：
4.8
通讯作者：
Yoshie, Ryuichiro
中科院分区：
文献类型：
--
作者：
Hu, Cheng-Hu;Ohba, Masaaki;Yoshie, Ryuichiro
采用RANS模型进行稳态模拟的传统方法可以预测交叉通风的充分流动特性，前提是所选湍流模型、边界条件和网格分辨率水平适当。然而，这些方法是不太令人满意的，如果我们更感兴趣的是脉动流量的统计描述。本研究采用大涡模拟方法，利用能够产生随时间变化的非定常来流的计算流体动力学代码，研究风引起的脉动流速。对两种风向进行了模拟：垂直于开口（情况1）和平行于开口（情况2）。计算结果与实验数据吻合较好。对于情况1，观察到的流速相对稳定，而对于情况2，它表现出非常不稳定的现象。观察结果表明，建筑物周围的气流模式显着影响通风流量。对于情况1，平均流量占主导地位的空气交换过程中，而对于情况2的波动流量似乎有更多的通风机制的影响。(c)2008爱思唯尔有限公司保留所有权利。
Traditional methods using steady-state simulations with RANS models may predict adequate flow characteristics of cross ventilation, provided the selected turbulence model, boundary conditions and level of mesh resolution are appropriate. However, these methods are less satisfactory if we are more interested in the statistical description of fluctuating flow rate. This study used a LES method to investigate the fluctuating flow rate induced by wind with a CFD code capable of generating time-dependent and unsteady inflows. Simulations were carried out for two wind directions: normal to the openings (case 1) and parallel to the openings (case 2). The results were in good agreements with experimental data. For case 1, the observed flow rate was relatively steady, whereas for case 2, it exhibited very unsteady phenomena. Observations indicated that the flow pattern around the building significantly affected the ventilation flow rate. For case 1, mean flows were dominant in the air exchange process, whilst for case 2 the fluctuating flows appeared to have more influence on the ventilation mechanism. (c) 2008 Elsevier Ltd. All rights reserved.