珠海市沿海风暴潮数值模拟试验研究

基于ELCIRC模型建立了适用于珠海市海域的风暴潮模型,以1713号台风“天鸽”路径为基础,通过改变台风入射角、台风登陆点、台风移速等方式构建登陆或者影响珠海市的台风路径,并进行风暴潮数值模拟计算,分析珠海市沿海风暴潮特征。结果表明:改变台风入射角时,珠海市沿海不同岸段的风暴潮将出现较大差异性;距离台风中心约15~100 km且位于台风右半圆的沿海地区将是风暴潮的重灾区;在珠海市的香洲区和斗门区沿岸,风暴增水总体随着台风移速变慢而呈现增大的趋势,但金湾区的情况则较为复杂,当台风移速为15~30 km/h时,在沿着台风“天鸽”的移动路径上会产生较强的风暴潮过程。

A Three-Dimensional Nearshore Hydrodynamic Model with Depth-Dependent Radiation Stresses

For the simulation of the three-dimensional（3D）nearshore circulation,a 3D hydrodynamic model is developed by taking into account the depth-dependent radiation stresses.Expressions for depth-dependent radiation stresses in the Cartesian coordinates are introduced on the basis of the linear wave theory,and then vertical variations of depth-dependent radiation stresses are discussed.The 3D hydrodynamic model of ELCIRC（Eulerian-Lagrangian CIRCulation）is extended by adding the terms of the depth-dependent or depth-averaged radiation stresses in the momentum equations.The wave set-up,set-down and undertow are simulated by the extended ELCIRC model based on the wave fields provided by the experiment or the REF/DIF wave model.The simulated results with the depth-dependent and depth-averaged radiation stresses both show good agreement with the experimental data for wave set-up and set-down.The undertow profiles predicted by the model with the depth-dependent radiation stresses are also consistent with the experimental results,while the model with the depth-averaged radiation stresses can not reflect the vertical distribution of undertow.

ELCIRC源程序代码分析

开放源程序代码ELCIRC是采用基于水平向无结构网格、垂向z坐标体系和半隐格式的欧拉-拉格朗日有限体积/有限差分方法来解浅水方程。研究了ELCIRC中除控制方程组求解以外的部分,分析了源程序在插值计算、拓扑结构、定解条件、分层信息和干湿法等技术上的具体操作,尤其是对欧拉拉格朗日模型特有的逆向追踪算法做了详细阐述。同时讨论了一些细节问题,在不恰当的地方给出一些参考和建议,避免小数做分母、相近数相减引起的较大误差。然而,这些经过实际应用的算法原理,可以为我们开发水动力学模型提供有价值的参考。

应用三维粒子轨迹跟踪模型模拟香溪河水藻增殖过程

三峡工程建成后将改变库区的水动力条件,会对库区及支流的水生态环境产生重要影响.因此,本文应用三维非结构海洋动力学模型ELcirc,以及考虑营养物质浓度、水温、水下光照强度和流速等因素影响水藻增殖的粒子轨迹跟踪模型模拟三峡库区支流香溪河的水流及水藻颗粒的输移.同时,采用室内弯道水槽试验资料对模型进行了验证,计算结果表明,验证后的模型可以较为精确地模拟弯道水流运动特性和弯道水流中的物质输移现象.采用验证后的模型研究了2007年9—10月三峡水库蓄水期香溪库湾的水流及藻类颗粒物质输移,结果表明,长江干流水体倒灌入香溪库湾产生回流,藻类颗粒向上游运动,考虑水藻生长过程的三维粒子轨迹跟踪模型可以较好地模拟水藻颗粒的垂向分布及水藻生长的水华过程.