本文關(guān)鍵詞： 龍卷風(fēng) 植被 CFD數(shù)值模擬 低矮建筑 風(fēng)壓　出處：《哈爾濱工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：龍卷風(fēng)具有生消迅速破壞力極強(qiáng)的特點(diǎn),所到之處樹木連根拔起、房屋受損嚴(yán)重,并且經(jīng)常卷積碎片,威力十分驚人。人類通過雷達(dá)實(shí)測、理論研究、實(shí)驗(yàn)?zāi)M、數(shù)值模擬等方法對龍卷風(fēng)有了更深刻的認(rèn)識。但是由于龍卷風(fēng)流場結(jié)構(gòu)復(fù)雜,卷積飛射物后對建筑破壞力更加驚人,很難短期內(nèi)完全模擬風(fēng)場對建筑的破壞�；谟�(jì)算流體動(dòng)力學(xué)(CFD)數(shù)值模擬方法研究龍卷風(fēng)風(fēng)場特性。建立風(fēng)場生成模型并選擇合理參數(shù)設(shè)置,將Spencer龍卷風(fēng)雷達(dá)實(shí)測數(shù)據(jù)作為風(fēng)場的入口邊界條件,通過在動(dòng)量、湍動(dòng)能和耗散率方程中添加源項(xiàng)來考慮風(fēng)場低空處的慣性阻尼,根據(jù)慣性阻尼與植被粗糙源對應(yīng)關(guān)系,分析不同疏密程度和葉面密度的植被對龍卷風(fēng)風(fēng)場特性的影響,力求通過模擬得到與實(shí)測龍卷風(fēng)一致的風(fēng)場結(jié)構(gòu)。通過分析風(fēng)場結(jié)構(gòu),把封閉平屋面低矮建筑放在風(fēng)場破壞力較強(qiáng)的位置并且考慮風(fēng)向角的影響,得到建筑物表面風(fēng)壓系數(shù)分布、3D渦量圖、速度矢量圖及建筑周圍流場跡線圖,分析封閉平屋面建筑在風(fēng)場中的受力特點(diǎn)。將8 m×4 m、4 m×4 m開洞形式的建筑放在受龍卷風(fēng)影響較大位置,分析洞口的存在對建筑內(nèi)外墻風(fēng)壓系數(shù)分布、渦量圖及速度矢量圖的影響,來確定洞口對建筑抗龍卷風(fēng)的作用�？紤]屋面坡度對建筑抗龍卷風(fēng)的影響,將15°和30°坡屋面建筑放在核心半徑處,變化不同轉(zhuǎn)角,分析其表面風(fēng)壓系數(shù)分布特征。采用滑移網(wǎng)格和動(dòng)網(wǎng)格技術(shù),通過建筑物的移動(dòng)來實(shí)現(xiàn)龍卷風(fēng)的等效移動(dòng),捕捉龍卷風(fēng)對建筑模型的動(dòng)態(tài)效果。研究建筑物表面風(fēng)壓荷載和建筑物周圍三維渦量圖,將等效移動(dòng)龍卷風(fēng)與靜止龍卷風(fēng)引起的建筑表面風(fēng)壓系數(shù)進(jìn)行對比,更好地揭示建筑物在等效移動(dòng)龍卷風(fēng)中受力狀態(tài)和破壞機(jī)理。
[Abstract]:Tornadoes are characterized by rapid destruction, uprooting trees, severely damaged houses, and often convolution fragments, which are extremely powerful. Human beings use radar measurements, theoretical research, and experimental simulation. Numerical simulation and other methods have a deeper understanding of tornadoes. However, due to the complex structure of tornado flow field, convolutional flying objects are more destructive to buildings. It is difficult to completely simulate the wind field damage to buildings in the short term. Based on the computational fluid dynamics (CFD) numerical simulation method, the wind field characteristics of tornadoes are studied. Taking the Spencer tornado radar data as the inlet boundary condition of the wind field, the inertia damping at the low level of the wind field is considered by adding source terms to the momentum, turbulent kinetic energy and dissipation rate equations, according to the relationship between the inertia damping and the vegetation rough source. This paper analyzes the influence of vegetation with different density degree and leaf density on the wind field characteristics of tornadoes, and tries to get the wind field structure consistent with the measured tornadoes by simulation, and analyzes the wind field structure by analyzing the wind field structure of tornadoes. By placing the closed flat roof low building in the position with strong wind field destructive force and considering the influence of wind direction angle, the distribution of wind pressure coefficient on the building surface and 3D vorticity map, velocity vector diagram and flow field track chart around the building are obtained. The stress characteristics of closed flat roof building in wind field are analyzed. The 8 m 脳 4 m 脳 4 m opening building is placed in a position which is greatly affected by tornado, and the distribution of wind pressure coefficient of the inner and outer wall of building is analyzed. The influence of vorticity diagram and velocity vector diagram is used to determine the effect of the hole on building tornado resistance. Considering the influence of roof slope on building tornado resistance, the roof building with 15 擄and 30 擄slope is placed at the core radius and varies at different angles. The characteristics of wind pressure coefficient distribution on the surface are analyzed. The equivalent movement of tornadoes is realized by moving buildings by using sliding grid and moving grid technology. To capture the dynamic effects of tornadoes on the building model, the wind pressure load on the building surface and the three-dimensional vorticity map around the building are studied, and the wind pressure coefficients of the building surface caused by the equivalent moving tornado and the static tornado are compared. The stress state and failure mechanism of buildings in equivalent moving tornadoes are better revealed.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU312.1

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