出水口位置对异重流运动及泥沙分布的影响

Influence of different outlet positions on density currents movements and sediment distributions

在实验室小环境下模拟大型水库及水库的分层环境,在水库温度分层条件下进行异重流实验,研究不同出水口位置条件下由水温分层引起的间层流现象,并探究分层环境下,出水口不同位置水库异重流运动的普遍规律及泥沙分布特性。结果表明:当入流泥沙浓度确定,出水口分别位于上、中、下层时,异重流的厚度、分离点深度、水跃高度和行进时间等参数数值差异较小;当入流泥沙浓度确定,上层出水口形成的间层流厚度基本沿程不变,中、下层出水口的间层流会因卷吸作用而卷吸周围清水导致间层流厚度局部增加;出水口位置确定,入流泥沙浓度基本不影响排沙比;入流泥沙浓度确定,上层出水口的排沙比远远大于中层和下层的排沙比。

The large reservoir and its stratified water environment could be simulated in a small laboratory environment. The density currents experiments were carried out under the condition of reservoir temperature stratification. The phenomenon of laminar density currents c a u s e d by water temperature stratification under different outlet positions was studied. Besides, exploration has been done about the universal law of the density currents movement and the sediment distribution characteristics in the stratified environment. As it turned out, w h e n the influent sediment concentration was determined and the outlet position was located at the upper, middle and lower levels respectively, the parameters7 numerical difference was small in terms of the thickness of the density current, the depth of the separation point, the hydraulic jump height and the travel time. W h e n the s e d iment concentration was determined, the thickness of the laminar density currents was almost constant along the way in the upper outlet position ; and the thickness of the same would increase partially due to the sucking effect from clear water in the middle and bottom outlet positions. When the water outlet position w a s set u n c h a n g e d , the influent sedimentconcentration basically did not affect sedimentation ratio. W h e n the s e d i m e n t concentration w a s d e t e r m i n e d , the sedimentation ratio at the upper outlet position was m u c h larger than that at the m i d d l e a n d b o t t o m outlet positions.