龙卷风风场与结构风荷载CFD数值模拟

发布时间：2018-06-11 20:14

本文选题：龙卷风 + CFD数值模拟　；参考：《哈尔滨工业大学》2013年硕士论文

【摘要】：龙卷风作为雷暴等极端气候的产物，有着生消迅速、难于监控、威力惊人等特点，且其在全球范围分布广泛并有随气候恶化而愈加频繁出现的趋势。人类通过灾后调查、雷达观测等手段已积累了较为丰富的龙卷风预报经验并完善了相应的防范机制，但是龙卷风复杂的流场结构和多样的破坏模式使得研究人员很难在短期内完全了解其发生机理及作用方式。本文采用基于计算流体动力学（CFD）的数值模拟研究龙卷风场下近地面处流场结构及其对建筑物风荷载的影响。本文的系统研究成果为建筑物的抗龙卷风设计提供崭新的途径和手段，丰富和发展结构抗风设计理论。本文具体研究内容如下：通过分析现有龙卷风的实验室模拟装置，基于通用商业CFD软件建立了龙卷风发生装置的数值模型，基于柱坐标的流场计算域包括三个子区域：底部入流区、中部对流区及上部出流区。以Spencer龙卷风的雷达实测数据作为入口边界条件，力求再现真实的龙卷风风场，，并着重研究了影响龙卷风特性的网格划分、湍流模型和边界条件等CFD数值模拟方面的影响因素，从而确立了龙卷风风场CFD数值模拟的相关参数。研究入口风速剖面和入射角剖面的变化对龙卷风风场结构的影响规律，进而获得不同尺度和不同强度的龙卷风风场模拟方法，采用核心半径刻画龙卷风风场的尺度，采用最大切向速度刻画龙卷风风场的强度，并通过涡流比沿高度变化规律阐释实际不同形状龙卷风的形成规律。研究龙卷风风场中单体建筑物的风荷载分布特性，考虑了建筑物所处距离龙卷风中心处不同位置和不同风向角对建筑物表面风压系数和整体风力系数的影响，通过后处理展示出不同风向角下建筑物表面的3D涡结构图，更好地阐述了龙卷风风场与建筑物的相互作用机理。
[Abstract]:As a result of the extreme weather, such as thunderstorms, tornado has the characteristics of rapid growth and elimination, difficult to monitor, powerful power and so on. It is widely distributed worldwide and has a tendency to appear more frequently with climate deterioration. But the complexity of the tornado flow structure and various failure modes makes it difficult for researchers to fully understand the mechanism and mode of action in the short term. In this paper, a numerical simulation based on computational fluid dynamics (CFD) is used to study the structure of the flow field near the tornado field and its influence on the wind load of the building. The systematic research results of this paper provide a new way and means for the design of building anti tornado, and enrich and develop the design theory of wind resistant structure.
Through the analysis of the laboratory simulator of the current tornado, a numerical model of the tornado generator is established based on the general commercial CFD software. The flow field based on the column coordinates consists of three subregions: the bottom inflow area, the central convective area and the upper outflow area.
Using the radar measured data of Spencer tornado as the entrance boundary condition, the real tornado wind field is reproduced, and the factors affecting the CFD numerical simulation of the tornado characteristics such as grid division, turbulence model and boundary condition are emphatically studied, and the relevant parameters of the CFD numerical simulation of the wind wind field of the tornado wind are established.
The influence of wind velocity profile and incident angle profile on the structure of tornado wind field is studied, and the simulation method of tornado wind field with different scales and different intensities is obtained. The core radius is used to describe the scale of tornado wind field, and the intensity of tornado wind field is depicted by the maximum tangential velocity, and the variation of eddy current ratio along the height is changed. The law explains the formation law of tornadoes in different shapes.
The wind load distribution characteristics of the single building in tornado wind field are studied, and the influence of different positions and different wind angles on the wind pressure coefficient and the overall wind coefficient of the building surface is considered. The 3D vortex structure of the building surface under different wind direction is displayed by post treatment, and the Dragon is better elaborated on the dragon. The interaction mechanism of wind wind field and building.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU312.1

【参考文献】