本文選題：計(jì)算流體動力學(xué)　切入點(diǎn)：熱液柱　出處：《海洋與湖沼》2017年06期

【摘要】：本文以沖繩海槽伊平屋北部熱液區(qū)(126o53.80′,27o45.50′)的現(xiàn)場水文數(shù)據(jù)作為背景條件,使用k-ε湍流模型模擬熱液柱的動力過程。模擬計(jì)算得到的羽流速度、溫度和湍流耗散率等基本物理量展現(xiàn)了熱液柱的時空演化過程。模擬結(jié)果顯示,羽流最大上升高度及中性浮力面高度與海底的距離分別為83.62m和68.97m,和2014年先導(dǎo)專項(xiàng)在此附近熱液區(qū)所觀測的溫度異常和鹽度異常的深度位置(離海底約66—86m)接近。羽流的上升速度滿足高斯分布,其半徑b與距噴口高度z-H成正比:b=0.0985(z-H),其中z為距海底高度,H為熱液煙囪體的高度。羽流的最大體積通量比噴口的初始值增加了878倍,達(dá)1.034m~3/s;在中性浮力面位置附近,動量通量達(dá)到最大值,為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)理論模型符合良好,在中性浮力面以上則呈現(xiàn)隨高度先增加后減小的特征。本文計(jì)算得到的平均卷挾率為α≈0.0807,與背景流較弱的熱液區(qū)的聲學(xué)現(xiàn)場觀測結(jié)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 偽 鈮，

本文編號：1712620