闸门释放重力流的大涡模拟研究  

Research on Lock-exchange Gravity Currents with Large Eddy Simulation

作　　者：叶家盛[1] 孙晧[1] 王雅萍[1] 黄河清[1] 

机构地区：[1]安徽工业大学建筑工程学院环境流体研究所,安徽马鞍山243032

出　　处：《安徽工业大学学报（自然科学版）》2013年第3期234-239,共6页Journal of Anhui University of Technology（Natural Science）

基　　金：国家自然科学基金项目(40972086;41172103)

摘　　要：采用大涡模拟(LES)数值计算有环境流体密度分层的闸门释放重力流,并分别与Sutherland等的实验结果及RANS的模拟结果进行对比分析。结果表明,采用标准Smagorinksy亚格子模型的LES和RANS在模拟重力的行进速度方面与实验接近,LES能更好地模拟实验所观察到的重力流头部和环境流体界面处的Kelvin-Helmholtz滚动结构,但LES模拟的2个方向相反的重力流之间的密度分层交界面处的波动比实验结果偏大。为此,进行了2种改进亚格子模型系数的大涡模拟,当Smagorinksy常数Cs取0.10时,交界面的波动有减小的趋势;采用近壁阻尼函数修正Cs系数时,将密度分层界面作为1个假想的固壁边界来处理,模拟效果较好。采用改进的亚格子模型的LES比RANS更适用于重力流的机理研究。The lock-exchange gravity current in density stratified ambient fluids is simulated with large eddy simulation （LES）. Simulated results are compared with those from the laboratory experiment and RANS simulation. The LES with standard Smagorinsky sub-grid scale （SGS） model and RANS modeling both showed good predictive ability for head velocity, while LES better reproduced the Kelvin-Helmholtz rollers at the interface between gravity clu＇rent and the ambient fluid. The simulated amplitude of the wave at the density stratified interface between the two opposite gravity currents is higher than that of the laboratory observation. Thus LES of the same flow with two modified SGS coefficients was conducted and found：when 0.10 used as Smagorinsky coefficient C,, the interface vibration becomes closer to that of experiment;when taken ambient fluid density interface as a virtual wall boundary, and using wall damping function for Smagorinsky coefficient C,, better simulated result is also＇ obtained. It is seen that modified LES offers more potential for studying gravity current mechanisms than RANS model.

关 键 词：闸门释放 重力流 雷诺平均 大涡模拟 

分 类 号：O352[理学—流体力学]