建筑屋面雪的热力学过程及风吹雪过程的耦合作用研究

建筑屋面的积雪暴露在复杂的自然环境中，受到热力学过程和风吹雪过程的影响，雪荷载大小及分布形式将发生一系列变化。为了精细化模拟屋面雪荷载，本项目将结合数值模拟、风洞试验和现场实测三种手段，研究屋面积雪在热力学过程和风吹雪过程的耦合作用下随时间的演变。在数值模拟中，选择合适的关联方法将屋面融雪模型与风吹雪模型进行耦合，利用耦合模型模拟屋面积雪在自然环境作用下的变化。开展风雪两相的风洞试验，探索热力学过程造成的积雪性质及积雪分布的改变对风吹雪过程的影响。在已经建好的东北哈尔滨实测基地，利用自然降雪和大比例尺建筑模型，探究两个物理过程对积雪的影响；通过设置对照试验，量化耦合作用，并验证数值模拟和风洞试验结果。依据本项目的研究成果，提出屋面雪荷载的简化计算方法，方便结构工程师使用。

Snow on building roofs is affected by the coupling effects of thermodynamic process and snowdrift process. The distribution of snow load will experience great changes for the exposure to environment. Thus, the project intends to refine the simulation of snow load on roof surfaces, using numerical simulation, wind tunnel test and field observation. In the numerical simulation, through a reasonable method, the roof snowmelt model is coupled to a snowdrift model to constitute a coupled model and then the evolution of the snow load in natural environment could be simulated by the coupled model. The two-phase wind tunnel test is performed to investigate the effects of the thermodynamic process on the snowdrift process. The field observation, which can validate the results of numerical simulation and wind tunnel test, is carried out in our built outdoor base. The outdoor base is located in frequency snowfall northeastern region, Harbin. Natural falling snow particle and large-scale roof models are adopted to explore the effects of roof heat transfer on the snow loads. The influence of the coupling factors can be quantified through controlled trials. Finally, based on the research results of this project, a practical method, which can calculate the snow loads, is proposed for the convenient application in structural engineering.