浑水异重流潜入理论模型及影响因素研究

Study of theoretical model and influence factors of turbid density current plunge

现有关于异重流潜入现象物理机制的研究较少,所建立的理论模型普遍只考虑流量和含沙量,事实上,异重流的潜入受多个水力因素共同作用。本文从异重流潜入过渡区的动量方程和能量方程出发,建立理论模型,并结合水槽试验予以模型参数的率定及模型的验证。该理论模型包含流量、含沙量、坡度、阻力系数、断面宽深比等多个水力因素,经分析发现:含沙量增大、流量减小、坡度增大、阻力系数增大、宽深比增大,更易形成异重流。随着含沙量减小,坡度的影响更明显,而阻力系数和宽深比的影响会减弱。

The researches on the plunging phenomenon of density generally concern on the densimetric Froude number at a plunging point,while the analysis of the plunge physical mechanism is few.A few theoretical models have been established only including water flow and sediment concentration.In fact,there are other hydraulic factors.In this paper,based on the momentum equation and the energy equation,a theoretical model of the plunging transition zone of density current is established.The parameters of the model were validated by the experiment.The theoretical model includes water discharge,sediment concentration,slope,resistance coefficient,ratio of width to depth.It shows that with the increase in sediment concentration,slope,resistance coefficient and ratio of width to depth and decrease in water discharge,the turbid density current would occur more easily.With the decrease in sediment concentration,the influences of resistance coefficient and ratio of width to depth would decrease;the influences of slope would increase.