共查询到18条相似文献，搜索用时 609 毫秒
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《浙江大学学报(A卷英文版)》2017,(10)
目的:探讨作用于大跨度曲面屋盖非定常气动力的特性,为考虑非定常气动力影响的大跨度曲面屋盖抗风设计提供理论参考。创新点:1.采用强迫振动试验;2.采用大涡模拟(LES)流入脉动风的生成方法;3.研究大跨度曲面屋盖非定常气动力特性。方法:1.通过强迫振动风洞试验方法探讨风速、强迫振动振幅、屋盖的矢跨比和缩减频率对非定常气动力的影响;2.采用计算流体力学数值模拟重现风洞试验,从而在更宽的缩减频率范围内分析非定常气动力的特性,并且通过可视化流场的分析探讨风与屋盖相互作用的机理。结论:1.屋盖的振动对屋盖表面的风压分布影响较大。2.屋盖的振动可能抑制屋盖背风面漩涡的脱落。3.根据风洞试验和数值模拟的结果分析得到的矢跨比、风速和振动振幅对气动阻尼系数和气动刚度系数的影响较小;气动阻尼系数和气动刚度系数主要随着缩减频率的变化而变化。4.气动刚度系数为正值,使得结构的总刚度减小,从而减小结构的固有频率;气动阻尼系数为负值,使得结构总阻尼增加。5.风洞试验和LES模拟结果的一致性可以说明,LES是一个能够有效研究非定常气动力特性的数值模拟方法。 相似文献
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谢应茂 《赣南师范学院学报》2007,28(3):27-30
采用传输矩阵法研究了一维光子晶体中介质层厚度的非关联高斯型随机分布对光学透射谱的影响.数值计算了个体随机结构的典型透射谱和不同平均无序度结构的集合平均透射谱,对集合透射模数与频率的关系进行了统计分析.结果表明:集合平均透射谱与平均无序程度、频率和介质层数有关,介质层厚度的高斯型随机分布导致带隙展宽. 相似文献
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拱型波纹屋盖风荷载数值模拟研究 总被引：1，自引：0，他引：1
基于谐波叠加法的基本原理,结合快速傅立叶变换,利用MATLAB编写了拱型波纹屋盖多点互相关的脉动风速程序.程序运行结果表明,结构各点模拟脉动风速时程的功率谱密度函数与目标函数、风速时程的自相关函数与目标自相关函数较为一致;相邻两点之间距离越近,互相关性越强,反之,则越弱.该研究结果对进一步研究拱型波纹屋盖结构风致振动时域分析具有重要意义. 相似文献
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球壳结构风压相关性研究（英文） 总被引：1，自引：0，他引：1
引入相关函数以描述不同矢跨比的球壳上2点间的风压相关性.根据风洞试验的风压测量数据,研究了2点间距离不同、2点连线与风向间角度不同时相干函数的大小.结果表明球壳结构上毗邻的2点在低频段具有强相关性,而非相邻点的风压相关性不明显.风压相关性随2点距离的减小而增大.距离相同时,风压相关性在顺风向最强,在横风向最弱.根据风洞试验数据,提出了球壳结构风压相关性指数模型,并给出了确定该模型的详细过程.结果表明该指数相关函数模型能恰当地描述距离较近2点间的相关性,且能较好地反映风向角变化的影响.此外,根据准定常理论对风压、风速间的相关性进行了研究,结果表明准定常理论对球壳结构风压、风速间的相关性不适用. 相似文献
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使用矢量瑞利-索末菲衍射积分公式推导出了矢量非傍轴高斯光束在杨氏实验中的传输公式,远场和傍轴公式作为特例给出,通过数值计算对其传输特性进行了研究. 相似文献
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对时变随机线性系统在坐标原点附近任意小范围内的摄动问题进行分析:当干扰噪声为连续函数时,统计规律服从高斯正态分布,并给出控制规律或控制函数;当该随机线性系统在控制过程中缺少先验约束条件和干扰噪声的采集时,通过补偿以消除噪声干扰给系统带来的不利影响,并通过决策因子递推迭代,得到最优控制策略和决策值.仿真结果表明,该系统在二次型性能指标条件下,能够获得线性二次型最佳对策. 相似文献
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We carried out a wind tunnel test to measure cladding loads for a high-rise building of 295 m in height, which would be located in the business center of Chongqing Municipality, P. R. China. The rigid model was used to determine fluctuating local pressures on the exterior surfaces of the building. The wind tunnel test results show the cr/tical zone of wind pressures on building surfaces in both standalone and interference conditions. The computational fluid dynamics （CFD） was conducted by using the FLUENT Code to compare with the wind tunnel test results, and the steady three-dimensional turbulent flow with Realizable k-ε as a turbulence model was used. The CFD results are agree with the wind tunnel test results in regards to distributions of wind pressures over a high-rise building＇s surfaces. 相似文献
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为研究拱型波纹屋盖在脉动风作用下的应力风振系数,考虑不同跨度、支座、不同矢跨比对应力风振系数的影响,利用ANSYS有限元分析软件对18 m、30 m跨波纹拱进行水平及竖向脉动风作用下的风振响应分析,得到了结构在不同位置处节点的应力及应力风振系数.计算结果表明:波纹拱应力风振系数随着结构的跨度增大而增大,随着矢跨比的增加而增加,支座约束为固支波纹拱的风振系数小于铰支波纹拱.该结论为结构设计、施工及同类型大跨轻型屋盖的风致振动提供参考和借鉴. 相似文献
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In this paper, the wind load on an arc-shaped canopy roof was studied with numerical wind tunnel method (NWTM). Three-dimensional
models were set up for the canopy roof with opened or closed skylights. The air flow around the roof under wind action from
three directions was analysed respectively. Wind pressure coefficients on the canopy roof were determined by NWTM. The results
of NWTM agreed well with those of wind tunnel test for the roof with opened skylights, which verified the applicability and
rationality of NWTM. The effect of the closure of skylights was then investigated with NWTM. It was concluded that the closure
of the skylights may increase the wind suction on the top surface of the roof greatly and should be considered in the structure
design of the canopy roof. 相似文献
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综合利用润扬结构健康监测系统(SHMS)风环境子系统实时记录的各种参数时程数据以及强风期间上桥实测强风样本,分析得到了桥址区实测强风的风速和风向、紊流强度、紊流积分尺度、紊流功率谱密度函数等特性,重点对比研究了台风与强北风特性之间的差异性.结果表明,与台风相比,强北风的平均风速略小、平均风向更加稳定;台风与强北风的实测紊流强度值均比规范建议值大;台风与强北风的紊流积分尺度之间无明显的规律性;就顺风向紊流功率谱而言,强北风与Kaimal谱更加吻合.研究结果为建立桥址区台风特性数据库,确定当地强风特性参数的合理取值提供了实测依据. 相似文献
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为了获得现场实测和风洞实验中测点较为稀疏地区的风压系数,以及弥补"坏点"造成的数据缺失问题,引入地理信息系统中有关数字高程模型的理念.以某单坡屋面为例,将实测结果进行网格化处理,并用风压系数代替高程数值,利用多种类型的插值方式获取待估位置的风压系数,最后分析对比不同方法的计算精度.结果表明克里格方法效果最好. 相似文献
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Wind-induced internal pressure response for structure with single windward opening and background leakage 总被引：3，自引：0，他引：3
Shi-ce YU Wen-juan LOU Bing-nan SUN 《浙江大学学报(A卷英文版)》2008,9(3):313-321
Theoretical analysis and wind tunnel tests were carried out to study wind-induced intemal pressure response for the structure with single windward opening and background leakage. Its goveming differential equation was derived by the Bemoulli equation in an unsteady-isentropic form. Numerical examples were provided to study the additive damping caused by background leakage in laminar and turbulent flow, and the influence of background leakage on fluctuating internal pressure response was quantized. A series of models for low-rise building with various opening ratios and background leakage were designed and wind tunnel tests were conducted. It is shown that the fluctuating intemal pressure reduces when the background leakage are considered and that the effect of background leakage can be predicted accurately by the governing differential equation deduced in this paper. 相似文献
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武浩浩 《荆门职业技术学院学报》2011,(5):18-21
针对NACA4412翼型风力发电机扰流流动特点,建立了二维和三维不可压缩湍流模型,并对基于流体连续性方程和N-S方程及k-ε湍流模型的二维流场进行数值模拟计算。采用多参考系计算（MRF）模型,用FLUENT模拟了流场内翼型截面的受力情况和速度分布情况,得到了NACA4412翼型风机的气动特性。 相似文献
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This paper discusses the unsteady aerodynamic behavior of long-span vaulted roofs. First, a forced vibration test in a turbulent boundary layer is conducted in a wind tunnel. The models are force vibrated in the first anti-symmetric mode to investigate the effects of wind speed, rise/span ratio, and the amplitude and frequency of forced vibration on the distributions of wind pressures and unsteady aerodynamic forces. Then, a large eddy simulation (LES) is carried out to clarify the physical mechanism of wind-roof interaction as well as to investigate the influences of a roof’s vibration on the flow field around the roof. From the results of the wind tunnel experiment and the LES, we discuss the characteristics of unsteady aerodynamic forces on a long-span vaulted roof over a wide range of the reduced frequency of vibration. The effect of unsteady aerodynamic forces on the dynamic response of the roof is also discussed. A comparison between the wind tunnel experiment and the LES indicates that the LES can be used effectively to evaluate the unsteady aerodynamic behavior. 相似文献