| 直立圆柱绕流流场中风速变化的影响因素研究 |
| Alternative Title | Influence factors research for the change of wind velocity in the flow field of flow around a vertical circular cylinder
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| 仇虎山 |
| Thesis Advisor | 武建军
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| 2011-05-31
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | 直立圆柱
数值模拟
Realizable k-e模型
欧拉两相流模型
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| Abstract | 荒漠化是一个全球性的重大环境问题，风蚀是荒漠化的主要形式之一。植株前后风场的变化是研究风蚀必不可少的内容。本学位论文利用Realizable k-模型和欧拉两相流模型对单个圆柱进行了三维湍流数值模拟，研究了圆柱直径为5mm、8mm和10mm，入口平均风速为7.3m/s和10.2m/s，沙粒相体积分数为0(净风场)、6%和10%的流动情况，入口平均风速通过计算一段适当长的无柱区域得到。并对计算结果进行了比较分析：
1. 沿高度方向，风速变化受床面剪切力的影响，随着高度增加，风速逐渐增大。越靠近床面，剪切力越大，而风速越小。
2. 沿流动方向，风速变化主要受圆柱阻碍作用，柱前后风速变化较大，柱后风速比柱前风速小，越靠近圆柱，受影响越明显。
3. 风速受圆柱直径、入口风速及沙粒相体积分数的影响，在圆柱前后距离柱相同位置处变化率不同。
4. 沙粒体积分数受圆柱直径、入口风速的影响在不同区域变化不同。
本学位论文分析了影响圆柱前后风场变化的主要因素，给出了沙粒体积分数的变化趋势，直观地反映了不同情况下圆柱前后风速的变化率，对于防沙治沙工程有一定的参考价值和实际意义。 |
| Other Abstract | Desertification is a very fateful environmental issue in the whole world. Wind erosion is one major form of the desertification. The change of wind field between the front and back of the plant is essential substance for the research of wind erosion. This master thesis used Realizable k-model and Eulerian Two-phase Model to simulate three-dimensional turbulent flow number for single cylinder. I analyzed some situations: the cylinder diameter is 5mm, 8mm and 10mm; inlet velocity is 7.3m/s and 10.2m/s; the volume fraction of sand is 0 (wind field), 6% and 10%. The inlet velocity is received by calculated a quite long column-free area. The results were compared and analyzed:
1. Along the height direction, the wind velocity is affected by the shear stress of bed. As the altitude increases, the wind velocity increases. Close to the bed, the shear stress reach to maximum and the wind velocity reach to minimum.
2. Along the flow direction, since the change of wind velocity is mainly precluded by the cylinder, the change of wind velocity is great between the front and back of the cylinder. At the front of the cylinder, wind velocity is weaker than back of the cylinder. The closer to the cylinder, the greater to the influence for wind speed.
3. The wind velocity is affected by cylindrical diameter, inlet velocity and volume fraction of sand. Even though at the same distance to the cylinder, the decrease range of wind velocity is different between the front and back of the cylinder.
4．Because of cylindrical diameter and inlet velocity , the volume fraction of sands changes with the different regions.
This master thesis analyzed the major factors that influent the change of wind velocity between the front and back of the cylinder, given the change trend of volume fraction of sands, and reflected the decreased range of the wind velocity under various situation. My research result is some reference value and practical significance for sand prevention and control project. |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/225765
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| Collection | 土木工程与力学学院
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Recommended Citation
GB/T 7714 |
仇虎山. 直立圆柱绕流流场中风速变化的影响因素研究[D]. 兰州. 兰州大学,2011.
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