冲绳海槽热液柱动力过程的数值模拟

发布时间：2018-04-05 01:28

  本文选题：计算流体动力学　切入点：热液柱　出处：《海洋与湖沼》2017年06期

【摘要】：本文以冲绳海槽伊平屋北部热液区(126o53.80′,27o45.50′)的现场水文数据作为背景条件,使用k-ε湍流模型模拟热液柱的动力过程。模拟计算得到的羽流速度、温度和湍流耗散率等基本物理量展现了热液柱的时空演化过程。模拟结果显示,羽流最大上升高度及中性浮力面高度与海底的距离分别为83.62m和68.97m,和2014年先导专项在此附近热液区所观测的温度异常和盐度异常的深度位置(离海底约66—86m)接近。羽流的上升速度满足高斯分布,其半径b与距喷口高度z-H成正比:b=0.0985(z-H),其中z为距海底高度,H为热液烟囱体的高度。羽流的最大体积通量比喷口的初始值增加了878倍,达1.034m~3/s;在中性浮力面位置附近,动量通量达到最大值,为0.156m~4/s~2,比初始值增加了882倍;浮力通量在中性浮力面以下和BM2000(Bloomfield et al,2000)理论模型符合良好,在中性浮力面以上则呈现随高度先增加后减小的特征。本文计算得到的平均卷挟率为α≈0.0807,与背景流较弱的热液区的声学现场观测结果相符。
[Abstract]:Based on the field hydrological data of 126o53.80 (27o45.50) in the northern Yipingwu area of the Okinawa trough, the K- 蔚 turbulence model is used to simulate the dynamic process of the hydrothermal column.The basic physical parameters, such as plume velocity, temperature and turbulent dissipation rate, obtained by simulation, show the spatio-temporal evolution process of hydrothermal column.The simulation results show thatThe maximum rising height of plume and the distance between neutral buoyancy surface height and sea floor are 83.62m and 68.97m, respectively, and the depth of temperature anomaly and salinity anomaly observed by the pilot project in 2014 (about 66-86m from the bottom of the sea) are close to each other.The rising velocity of the plume satisfies Gao Si's distribution, and its radius b is proportional to the height of the nozzle z-H, where z is the height of the hydrothermal chimney from the bottom of the sea.The maximum volume flux of the plume is 878 times higher than the initial value of the nozzle to 1.034 mm2 / s, and near the neutral buoyancy surface, the momentum flux reaches the maximum value of 0.156 mm2 / s-2, which is 882 times higher than the initial value.The theoretical model of buoyancy flux below neutral buoyancy surface is in good agreement with that of BM2000(Bloomfield et alcan2000. Above neutral buoyancy surface, the buoyancy flux increases first and then decreases with the height of neutral buoyancy surface.The calculated average volume carrying ratio is 伪 鈮，

本文编号：1712620