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。
Abstract
A vertical two-dimensional RNG k-ε 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 under the same condition; 2)the relation between head velocity and the cubic root of buoyance flux is not a strict proportional 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
Key words
density current /
slope /
head velocity /
numerical simulation /
RNG k-ε turbulent model
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参考文献
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