论文总字数：27430字

摘 要

在我国，洪水灾害发生次数多且频率高，具有极大毁灭性，危害程度非常高。洪水的冲击作用历时短，作用范围有限，会对建筑结构造成极大的危害，严重时甚至会引起建筑物的损毁，尤其是在山区的村镇中，危害更大。本文根据计算流体力学（CFD）的原理与方法，利用Fluent软件对山区洪水作用下房屋迎流面压力进行数值模拟与分析。

通过对不同洪水流速、不同斜坡长度、不同房屋间距、不同坡度情况下的冲击压力大小，以及冲击压力分布的数值模拟结果进行分析，得到迎流面压力的变化规律。房屋迎流面表面冲击压力基本随着高度的增大而减小，两侧边缘由于受到边界条件影响，所受压力值相比中部同一高度的偏小。冲击压力峰值随着洪水初始水流速度的增大而增大。洪水水流速度较低时，房屋迎流面所受冲击压力峰值随着初始间距的增加而增大；洪水水流速度较高时，适当地增加洪水与房屋初始距离，能够一定程度上降低冲击压力峰值。房屋间距对冲击压力大小和分布的影响不明显。流动稳定后，迎流面的压力最大值随着房屋间距的增大而减小，压力峰值区域随着房屋间距的增大而缩小，压力等值线随着房屋间距的增大变得稀疏。迎流面冲击压力峰值随着斜坡坡度的增加而增大。当坡度由6°增加至8°时，迎流面冲击压力峰值增幅最大。

本文的研究工作为山区房屋的抗洪设计提供了依据。

关键词：洪水；冲击压力；数值模拟；Fluent

Abstract

In China, flood disaster which is of great destructive power occurs frequently. Due to the short duration and limited scope of the impact of flood, it will actually cause great damage to the building structure, and even cause the damage of the building when it is serious, especially in the villages and towns in the mountainous area. According to the principle and method of computational fluid dynamics (CFD), this paper uses Fluent software to carry out numerical simulation and analysis of the inflow surface pressure of houses under the action of mountain flood.

By analyzing the numerical simulation results of impact pressure magnitude and impact pressure distribution under the conditions of different flood flow velocity, different slope length, different house spacing and different slope, the variation law of the pressure on the flow surface is obtained. The impact pressure on the flow surface of the building decreases with the increase of the height. Due to the influence of boundary conditions, the pressure on both sides of the edge is smaller than that on the same height in the middle. The peak impact pressure increases with the increase of the initial flow velocity. When the flood flow velocity is low, the peak impact pressure on the housing flow surface increases with the initial spacing. When the flood flow velocity is high, increasing the initial distance between the flood and the house can reduce the peak impact pressure to a certain extent. The impact of housing spacing on the size and distribution of impact pressure is not obvious. After the flow is stable, the maximum pressure of the flow front decreases with the increase of the housing spacing, the pressure peak area shrinks with the increase of the housing spacing, and the pressure contour line becomes sparse with the increase of the housing spacing. The peak impact pressure increases with the increase of the slope. When the slope increased from 6 ° to 8 °, incident flow surface impact pressure peak amplitude is the largest.

The research work of this paper provides basis for flood resistance design of houses in mountainous areas.

Key words: flood; impact pressure; numerical simulation; Fluent

目 录

摘要 …………………………………………………………………………………………………………Ⅰ

Abstract ……….…………………………………………………………………………………………Ⅱ

第一章 绪论 1

1.1 研究背景 1

1.2 研究现状 2

1.3 本文研究内容 3

第二章 数值模拟方法及模型验证 4

2.1 数值模拟方法 4

2.1.1 CFD概述 4

2.1.2 CFD三大流动基本方程 6

2.1.3 Fluent软件 6

2.1.4湍流模型 7

2.1.5 多相流模型 8

2.2 模型简化及验证 9

2.2.1 模型简化方案 9

2.2.2 边界条件与Fluent参数设定 10

2.2.3 计算模型测试 11

第三章 不同坡长和流速对冲击压力的影响 14

3.1 计算模型建立 14

3.2 数值模拟结果与分析 14

3.2.1 洪水冲击过程 14

3.2.2 房屋迎流面压力分布 17

3.2.3 迎流面冲击压力峰值变化 19

3.3 本章小结 22

第四章 不同房屋间距对冲击作用的影响 23

4.1 计算模型建立 23

4.2 数值模拟结果与分析 23

4.2.1 房屋迎流面压力峰值变化 23

4.2.2 房屋迎流面压力分布 25

4.3 本章小结 26

第五章 不同坡度对冲击力大小的影响 28

5.1 计算模型建立 28

5.2 数值模拟结果与分析 28

5.3 本章小结 29

第六章 结论与展望 30

6.1 结论 30

6.2 展望 31

参考文献（References） ………………………………………………………………………32

致谢 .………………………………………… ………………………………..……………...34

绪论

研究背景

在世界上各种各样的自然灾害中，由于发生的次数较多，频率高，容易造成各类人员伤亡与经济损失，突发性强，影响的范围非常大，洪水灾害被认为是危害程度非常高的自然灾害之一。而我国由于特殊的地理环境和气候特点，使得年降雨量区域分布不均匀，导致洪水灾害频繁发生。

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