【作者】 张默；

【导师】 肖仪清；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2008， 硕士

【摘要】 我国是沙尘天气频发地区,据粗略统计,我国每年因风沙危害造成的直接经济损失高达540亿元人民币。近年来,人们越来越意识到风沙研究的重要性。20世纪80年代,有研究者开始对风沙运动过程进行数值模拟,目前已提出了形式各异的模型。对于超高,大跨和轻质建筑物,结构对风作用的敏感性大大增强,致使风荷载成为此类建筑控制设计的主要荷载之一。目前,土木工程领域利用CFD方法研究风沙共同作用下建筑物表面的风荷载还非常少见。本文正是基于商业CFD软件FLUENT,对风沙共同作用下建筑物周围风场作了数值模拟。在建筑物静风荷载的模拟研究中,首先确定了湍流模拟方法——剪切应力模型(SST)。然后分别对两种典型模型:AIJ模型和CAARC模型的数值模拟结果与风洞试验结果进行了对比分析,得出数值模拟结果与风洞试验结果有很好的一致性,证明了利用CFD方法模拟建筑物表面风压的准确性。在建筑物风沙荷载的模拟研究中,首先,根据我国建国四十多年来的风沙天气统计报告,选用北京地区和甘肃地区发生的最大沙尘暴统计结果,确定了大气气溶胶的质量浓度极大值,沙粒的折算粒径,沙粒密度等。其次,在静风荷载结果的基础上加入第二相(颗粒相),假设沙粒浓度均匀分布,沙粒相与气体相没有相对滑移,且沙粒相与气体相单向耦合,即沙粒相对气体相无作用。最后,根据模拟结果进行对比分析:根据沙粒浓度不同,风速不同,对AIJ模型和CAARC模型的表面风压以及沙粒沉积进行了研究,验证了CFD在模拟两相流方面的可行性。更多还原

【Abstract】 China is a region of frequent sandstorm weather, according to the roughly statistics, the annual damage caused by sandstorms against direct economic losses is up to 5.4 billion yuan. More and more people are aware of the importance of sandstorm research. In the 1980s, some researchers have started to researche the sandstorm movement numerical simulation. In the current , many model forms have been proposed. For high, long-span building, the wind effect on the the structures has been greatly enhanced, resulting in wind load control design of buildings as one major load. At present, in the civil engineering field, the use of CFD methods to study the effects of Wind-Blown-Sand load on the surface of buildings is very rare. This article is based on commercial CFD software FLUENT, researching of the numerical simulation of wind loads on the surface of building and Wind-Blown-Sand Two Phase Flow field around the building.In the case of the numerical simulation of wind loads on the surface of building, first of all, determining the simulation of turbulence model - shear stress model (SST). Secondly, AIJ model CAARC model and numerical simulation results of wind tunnel tests and the results were compared and analyzed the results of numerical simulation and wind tunnel test results have a good consistency to prove that the use of CFD simulation of the surface of buildings the accuracy of the wind .In the case of the numerical simulation of the load of wind-blown-sand two phase flow of building, first of all, according to the records of our country for more than four decades of the sandstorm weather reports, selecting of the biggest sandstorm statistical results in Beijing and Gansu , the quality of the atmospheric aerosol maxima concentration conversion of particle size. Secondly, in the case of the load on the basis of the second phase (the particle phase), sand particles have equivalent size, on the basis of the results of wind load ,adding the second phase (the particle phase), assuming that the concentration of uniform sand, sand with gas phase and there is no slippage, and the gas phase sand coupler with a one-way coupling, that is, the sand has no relative of the gas phase.The last analysis: same wind sand; different concentrations, Wind sand, different concentrations.The last, according to the simulation results: the same volume fraction of sand, different wind speeds; the same volume fraction of sand, different wind speeds, AIJ and CAARC models have been respectively studied. AIJ on CAARC model and the model of wind and sand deposited on the surface have been studied to verify the CFD simulation in two-phase feasibility.更多还原