斜坡上的密度流数值模拟研究  

Numerical Simulation of Density Current on a Slope

作　　者：米博宇[1] 张小峰[1] 任实[2] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,武汉430072 [2]中国长江三峡集团公司,湖北宜昌443133

出　　处：《长江科学院院报》2017年第7期60-64,共5页Journal of Changjiang River Scientific Research Institute

摘　　要：为了探讨均匀密度环境水体中斜坡密度流的运动规律,建立了立面二维RNG k-ε紊流数学模型,通过与已有试验资料对比,验证了该模型的合理性与准确性。利用该模型模拟不同坡角和流量下的斜坡密度流,研究结果表明:密度流头部流速与坡角具有一定的函数关系,存在一个最优坡角使得相同条件下的头部流速最大;头部流速与浮力通量的三次方根之间并非严格的正比例函数关系,在流量较小或较大时将发生偏离;密度流运动过程中,头部形态不断扩大,头部的厚长比逐渐减小;头部扩大的速率随着坡角和流量的增大而增大,最后逐渐趋于一个稳定速率。研究结果能够帮助进一步了解斜坡密度流的运动规律。A vertical two-dimensional RNG k-s turbulent model is established and its reasonability and accuracy are verified by comparison with existing experimental data. Density current on a slope in the presence of different slope gradients and discharges is simulated, and results reveal that 1） the head velocity of density current has a function relationship with the slope gradients, and there is an optimal slope gradients which maximizes the head velocity un-der the same condition; 2） the relation between head velocity and the cubic root of buoyance flux is not a strict pro-portional function, deviating under small or large discharge; 3 ） the head shape is enlarged in the motion process of density current, and the ratio of thickness to length of the head decreases gradually; 4） the growth rate of the head increases with the increase of slope gradients and discharges, and finally tends to a steady rate. These results could help further understand the motion pattern of density current on slope.

关 键 词：密度流 斜坡 头部流速 数值模拟 RNG K-Ε紊流模型 

分 类 号：TV131[水利工程—水力学及河流动力学]