| 摘要: |
| 使用Casulli等(2000)的数值方法建立了基于正交非结构网格的U型渠道的三维近岸正压水动力数值模型, 检验了模型使用 ELM(Eulerian-Lagrangian Method)方法处理平流项时, 物理流场的定义对模拟结果的作用。 数值试验和结果分析说明, 使用 ELM 方法计算平流项所需的物理流场对计算结果影响明显, 而目前常用的两种物理流场定义方法都存在一定不足——水位计算值对流速变化的反映不灵敏或者会产生小扰动等。针对常用物理流场定义方法的不足之处, 作者在 Casulli 方法的基础上利用对多边形切向流速分量进行平均的方法改进了物理流场定义, 抑制了小扰动。
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| 关键词: 非结构网格, 数值模型, ELM 方法, 物理流场 |
| DOI：10.11693/hyhz201004023023 |
| 分类号: |
| 基金项目:国家重点基础研究发展(973)计划, 2006CB400602、2007CB816003 号、我国近海海洋综合调查与评价专项, 908-02-01-04号、海洋公益性行业科研专项经费项目,200705013 号、国家海洋局第二海洋研究所基本科研业务专项资金项目, JG200810 号。 |
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| THE PHYSICAL CURRENT VELOCITY DEFINITION AND ITS IMPROVEMENT IN THE 3-D ORTHOGONAL UNSTRUCTURED GRID NUMERICAL MODEL |
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LIU Xiao-Hui1, DONG Li-Xian1, Ralph T. Cheng2
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1.State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration;2.Water Resources Division, USGS, USA
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| Abstract: |
| A 3-D coastal barotropic hydrodynamic numerical model in a U-channel covered with an orthogonal unstructured gird was established using the numerical scheme of Casulli (2000). The effects of two current velocity definitions of physical current field for the advection term calculated by the Eulerian-Lagrangian Method (ELM) were examined. The numerical experiments and the results analysis showed that the results were obviously influenced by the definition of the physical current field used by ELM. Some disadvantages exist using the two common methods, such as insensitive feeding back between the velocity and elevation and existence of small oscillation. A new physical current field definition based on Casulli’s scheme was proposed to inhibit the small oscillation in the orthogonal unstructured grid numerical model.
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| Key words: Unstructured grid, Numerical model, Eulerian-Lagrangian Method, Physical current field |
