底部薄板附近的水流及泥沙运动特性

通过水槽实验探讨了在饱和来沙条件下底部薄板附近的水流、泥沙运动特性,包括不同薄板高度、与水流不同夹角的安装方向等情况下,单个底部薄板附近的水流结构、泥沙运动规律、底部薄板的导沙特性及其附近的冲淤现象,以及底部薄板群体的导沙特性。试验结果表明,实验使用的薄板的长度对实验结果影响很大,过短的薄板实验根本观察不到薄板前冲刷沟内的沙波运动,而该沙波运动严重影响薄板的导沙效应。底部薄板附近的水流结构具有强烈的三维特性,流场复杂,对于一定的薄板,水流夹角、沙波的运动是影响薄板的导流导沙促淤的主要因素。

Flow and sediment motion around submerged vanes

The characteristics of flow and sediment motion around submerged vanes were investigated in a wide open uniform channel flume.The flume bed was uniformly paved using lightweight material of plastic pellets.The thin vanes had different heights from 5 cm to 20 cm.The shortest vanes were 0.5 m long.Different attack angles of the vanes to the approaching flow were achieved from 30° to 90°.It was found that the length of vane used in experiments is very important because the bedforms would not be able to be observed at the scoured trench at the vane.It became easier for bedload particles to climb over the vane and hence the effectiveness of the vane on sediment diversion was largely reduced.The experimental observation revealed that the flow around submerged vanes were strongly three dimensional turbulent with different helical flow structures.The attack angle and bedforms were major factors affecting the effectiveness of certain vane on flow and sediment diversion.