明渠中跌坎后突扩分离流数值研究  

NUMERICAL SOLUTION OF BACKWARD-STEP SEPARATION FLOW IN OPEN CHANNEL 1)

作　　者：刘沛清[1] 邓学蓥[1] 

机构地区：[1]北京航空航天大学流体力学所

出　　处：《力学学报》1998年第1期9-19,共11页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家博士后管理委员会基金

摘　　要：利用大涡模拟技术，对明渠中跌坎后的二维突扩分离流结构进行了数值模拟，探讨了这类典型分离流各特征区的流动性质，分析了再附区壁面上不同测点处脉动压力的统计特征，并与试验结果进行了比较．在数值模拟中，采用了弱压缩流的控制方程和非均匀网格系统．By use of the large-eddy simulation, numerical solutions of two-dimensional backward-step separation flows in open channels are obtained. The behavior in different regions for step-induced separation flow and statistical characteristics for fluctuation pressure on the wall within the reattachment zone is investigated. The results obtained are compared with the experimental values. A weakly compressible flow model and a non-uniform grid are used in this paper. The calculated results show that the method of the large eddy simulation can not only predict the main characteristics of step-induced separation flows in open channels, but also give the fine structures of this flow. Through analysing fluctuating pressures on the wall within the reattachment region, profiles of mean square root values of pressure fluctuations, integral time scales and Energy spectrum E(f) and auto-correlation functions of pressure fluctuations are given in details. Comparison with experimental results of pressure fluctuations shows that the main turbulent characteristics of pressure fluctuations predicted by the large eddy simulation are basically reasonable. Within the reattatchment region, the mean square root values of pressure fluctuations on the wall are larger due to impingement of the main flow and the frequency width is located between 0～10 Hz.

关 键 词：大涡模拟 分离流 跌坎 明渠流 数值模拟 

分 类 号：TV133[水利工程—水力学及河流动力学]