桥台局部冲刷坑内水流运动的三维数值模拟  

Numerical simulation of the three-dimensional flow in a scour hole around an abutment

作　　者：陈小莉[1] 马吉明[1] 

机构地区：[1]清华大学水利水电工程系水沙科学与水利水电国家重点实验室,北京100084

出　　处：《水动力学研究与进展（A辑）》2007年第6期689-695,共7页Chinese Journal of Hydrodynamics

基　　金：高等学校博士学科点专项科研基金(20060003039)

摘　　要：局部冲刷是河道中丁坝、桥台等破坏的重要因素。这些建筑物周围绕流流场和泥沙运动十分复杂,对冲刷的机理及平衡条件的研究还有待于进一步深入。文中采用k-ε模型对桥台周围平衡冲坑内的流场进行了三维数值模拟,计算结果正确反映了建筑物周围的流速分和紊动动能的分布;根据流场分布分析了冲坑内的旋涡分布规律及其与冲刷的关系,阐述了主旋涡向螺旋旋涡的转化以及冲坑内水流的能量耗散机理。冲坑内的床面切应力的分布反映了床面冲刷平衡条件,数值模拟得到的床面切应力分布表明颗粒运动受到斜坡上重力作用的影响,同时在紊动剧烈的区域还受到旋涡的影响。Local scouring is an important factor in the destruction of spur- and abutment-like structures. As flow field and movement of sediment is complex around the structure, further research on the mechanism of the scouring process and the stopping conditions of scour is still in need. In this paper, the k-ε model is used to simulate the three-dimensional flow around an abutment. It is shown that the numerical results for the flow field and the turbulence distribution are in good agreement with experimental data. Thus the vortex distribution in the scour hole in relation to the local scouring are analyzed. The translation from a main vortex to a helical vortex and the mechanism of energy dissipation in the scour hole are explored. The bed sheer stress reflects the ceasing condition of scouring and the influences of the gravity and the turbulent vortex in highly turbulent areas on the sediment motion.

关 键 词：局部冲刷 三维数值模拟 泥沙起动 床面切应力 

分 类 号：O242[理学—计算数学]