中文摘要：

基于FLUENT软件，模拟了多孔介质底床内部孔隙流和表面自由流共同作用下的流场结构。结果显示，主流区水流通过圆柱体顶部时会发生脱溜一靠溜过程；且该过程中水流的流态不对称；孔隙水流的流速与紊动强度远小于切向主流区；孔隙内紊动强度随孔隙所在深度的增大而逐渐降低，且降低幅度逐层减小。

英文摘要：

The commercial CFD software FLUENT was introduced to study the flow characteristics on the boundary layer of permeable bed and within it. The permeable bed is subjected to free-surface flow in an open channel. The results show the existence of fluid separation close to the cylinder and fluid re-attachment close to the downstream cylinder. The flow structure is asymmetry in this process. The results indicate that the velocity and turbu- lence intensity in the pores are much smaller than in the tangential flow zone above the bed. The results have also shown that the flow turbulence intensity in pores descends with increase of depth below the bed surface, and the descending rate gets down as well.