溃坝水流三维湍流的试验与数值分析

采用假定溃口形状,选取临界漫顶及坝体完全淹没2组不同流量,进行定床物理模型试验,测量了溃口内部水流的垂线流速分布.采用CFD软件FLUENT对2组三维溃坝水流进行全流场湍流数值模拟,其结果与试验值吻合较好,同时较为精细地捕捉到了坝前水位稳定后溃坝水流三维流场、湍动能和壁面剪切应力.结果表明:高强度壁面剪切应力可能为坝体侵蚀主要因素,在坝顶及溃口与坝面的连接处壁面剪切应力及湍动能出现极大值,强湍动能将使得侵蚀的泥沙迅速扩散到水体当中,随着水流的运动向下游输移.三维流动的存在,使得泥沙向下游输运的过程中先向溃口内部集中,到达下游河道后再逐渐扩散到整个河道中.小流量情况下,这一趋势不太明显,随着漫顶流量的增大这一趋势明显增强.以上水力条件可能为溃口迅速展宽、降低的主要因素.

Experiment study and 3D numerical simulation of dam break turbulent flow

Fixed bed experiments are carried out to study the vertical velocity distributions of flow within dam breach under the conditions of 2 different inlet discharges.CFD software FLUENT is used to make a study of the 3D dam-break turbulent flow.Fairly good agreements are shown between computed and measured results.3D distributions of flow velocity and turbulent kinetic energy and wall shear stress on dam surface are captured.The result implies the wall shear stress may be the main factor of the dam erosion duri...