| 李玲,木村繁男.大气绕山体的运动及其输移特性的研究[J].计算力学学报,2007,24(4):477~481 |
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| 大气绕山体的运动及其输移特性的研究 |
| Numerical modeling of atmospheric flow and dispersion around a mountain |
| 修订日期：2005-06-30 |
| DOI：10.7511/jslx20074093 |
| 中文关键词: 数值模拟,分层大气流动,山体绕流,污染物输移 |
| 英文关键词:numerical modeling,stratified flow,atmospheric flow around a mountain,pollutant dispersion |
| 基金项目:by SRFfor ROCS,SEM. |
| 李玲 木村繁男 |
清华大学水利水电工程系 北京100084(李玲)
，日本金沢大学自然与环境技术研究所 金沢920-8667日本(木村繁男)
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| 摘要点击次数: 1706 |
| 全文下载次数: 11 |
| 中文摘要: |
| 对分层大气山体绕流的流动模式及扩散输移特性进行了数值模拟。采用隐式时间离散方法在贴体网格系统下求解雷诺平均的N-S方程,计算结果描述出大气流动的特征,证实了分层(以Froude数为特征参数,定义为F=U/NH,U为来流风速,N为Brunt-Vaisala频率,H为山体高度)变化对山体绕流流态的影响。数值结果表明:当Froude数大于4.0时,山体绕流的流动不再依赖于大气分层的变化。当Froude数介于4.0和1.0之间时,流场中出现了Lee波,并随着Froude数的进一步减小,流动分离发生及Lee波破碎现象。同时模型也预测了在各种流动模式下大气中夹杂着的污染物绕山体的传输特性,表明大气的分层现象对污染物的分布有着非常重要的影响。 |
| 英文摘要: |
| A series of numerical experiments had been conducted to investigate the flow patterns and dispersion characteristics around a mountain under stably stratified flow.The two-dimensional model equations,based on the time-dependent Reynolds averaged Navier-Stokes equations,were solved numerically using an implicit time integration in body-fitted grid arrangement.The behavior of the flow is clarified to ascertain the effects of changes in the stratification,which is characterized by the Froude number F=U/NH(Where U is speed of the approaching wind,N is the Brunt-Vaisala frequency,and H is the mountain height). The numerical results suggest that the flow structure is independent of stratification when F>4.0.The model predicts lee wave generation as the Froude number is decreased from 4 to 1,then flow splitting,wave breaking phenomena happen as F is further decreased to less than 1.0.Further,the model-predicted concentration fields when the contaminant is coming with the approaching wind show that the stratification of atmospheric flow has significant effects on the dispersion pattern. |
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