来流湍流对山区复杂地形风场的作用机理研究

It is of great importance to comprehensively understand the characteristics of wind flow over complex mountainous terrain for wind resistant design of wind sensitive structures and wind energy development in mountain area. Wind flow over complex terrain depends strongly upon the upstream approaching environment, so it is very necessary to consider the effects of a large-range upstream topography of the target complex mountainous terrain in wind tunnel tests. In this project, the upstream approaching environment of complex terrain is equivalent to inflow turbulence with uniform ground roughness according to the method of load code, and then influences of different kinds of inflow turbulence on wind characteristics over complex terrain are studied, aiming to deepen understanding of wind flow over complex mountainous terrain. The first actively controlled wind tunnel in China is used in this project to generate inflow turbulence. And wind tunnel tests will be carried out to study the action mechanism of inflow turbulence on speedup ratio, turbulence intensity and spatial correlation of wind field over four different complex terrain models: two single two-dimensional hills (one low and one steep) and two single three-dimensional hills (one low and one steep), through gradually changing the mean velocity profile, turbulence intensity and turbulence integral scale of inflow turbulence. This project will be helpful to fully understand the characteristics of wind flow over complex mountainous terrain, and can not only guide wind engineering practice in mountain area, but also provide data support to improve the wind load code. So it is believed that this project meet the urgent need of western development strategy of China.

全面了解山区复杂地形的风场特性对山区风敏感性结构的抗风设计和风能资源的开发利用都至关重要。由于复杂地形风场严重依赖于上游来流环境，故在风洞试验中就需要考虑目标区域上游大范围地形起伏的影响。本项目借鉴荷载规范的方法，将复杂地形的上游来流环境等效为均匀粗糙度条件下的来流湍流，进而研究不同来流湍流对复杂地形风特性的影响，旨在加深对山区复杂地形风场的了解。利用国内首座主动控制风洞生成来流湍流，并通过依次逐渐改变其平均风剖面、湍流强度和湍流积分尺度，来研究平缓/陡峭孤立二维山体、平缓/陡峭孤立三维山体等四个地形上的平均风增速比、湍流强度和空间相关性等风场特性随来流湍流的变化规律及机理。本项目有助于深入了解山区复杂地形的风场特性，不仅能够指导山区的风工程实践，也可为完善风荷载规范提供参考，适应我国西部大开发的迫切需要。

全面了解山区复杂地形的风场特性对山区风敏感结构的抗风设计和风能资源的开发利用都至关重要。由于复杂地形风场严重依赖于上游来流条件，故在传统风洞试验中就需要模拟目标区域上游大范围的地形起伏，但受到模型缩尺比的限制，难以同时模拟地表细节，从而影响试验精度。借鉴荷载规范的做法，将复杂地形上游来流环境等效为均匀粗糙度条件下的来流湍流，进而研究不同来流湍流对复杂地形风特性的影响，旨在加深对山区复杂地形风场的了解。本项目的主要研究内容是采用主动控制风洞结合数值模拟生成来流湍流，并通过依次逐渐改变其平均风剖面、湍流度剖面和积分尺度剖面，来研究平缓/陡峭孤立二维山体、平缓/陡峭孤立三维山体等四个地形上的平均风增速比、湍流强度和空间相关性等风场特性随来流湍流的变化规律及机理。本项目的主要结果可概括为以下三个方面：（1）进一步深化基于局部微分求积法结合简化循环方法的来流湍流模拟技术，探讨微分求积数值求解流函数—涡度方程中所遇到的流函数超约束问题；（2）采用Boussinesq假设，通过大涡模拟研究温度层结效应对山体绕流平均风和湍流度的影响；（3）采用主动控制风洞研究来流湍流参数变化对山体绕流的影响，发现来流湍流度对山体绕流的影响与来流积分尺度密切相关。本项目有助于深入了解山区复杂地形的风场特性，不仅能够指导山区的风工程实践，也可为完善风荷载规范提供参考，适应我国西部大开发的迫切需要。.在执行课题的三年间，在国内外学术刊物上发表了标注本课题的SCI论文4篇、EI论文1篇，参加国际学术会议并发表标注本课题的学术论文两篇，协助培养博士生、硕士生各一名。