The Numerical Simulation Study On Wind-induced Snowdrift Of Folding Reticulated Shell

Folding reticulated shell tent camping is widely used in civil and military field.Such building's protective layer and structural layer are weaving materials,which lead to the dead-weight of structure has a small proportion in the whole load weight.So it belongs to the typical light housing that the wind and snow load is the main control loads of the structural design.There are relatively deep researches on wind load.But for snow load,wind-induced snow drifting effect will cause snow's uneven distribution in folding reticulated shell roof surface.It often leads to partial or whole structure collapse.What's more,current "load code for the design of building structures"(GB50009-2012)is based on previous design experience,international standards and foreign relevant information,and only synoptically give out the snow distribution coefficient of the typical roofings,which has not applied to the springing of the light roof structures of unique appearances and are sensitive to the snow load.So it is necessary to make further research and discussion on the wind-induced snow drifting effect of folding reticulated shell structure.In present research methods for wind-induced snow drifting,field measurement can obtain the most accurate data,but it has long cycle and largely limited by many factors such as natural conditions;experimental research make the cost too high because of the limitation of test conditions and similarity criterion.With the rapid development of computer technology,CFD(Computational Fluid Dynamics)numerical simulation technology,which has short cycle,low cost,and the advantages of satisfying the similarity and high repeatability simulation easily,has been used in the study of the motions of the snow particles widely and deeply.In order to conduct further study on wind-induced snow distribution laws of folding reticulated shell surface,on the basis of Euler-Euler method and the fundamental assumptions of air and snow are to be one-way coupled and both continuous,considering the saltation and suspension movement patterns of snow drifting,using mixture multiphase flow model theory of the large general computational fluid dynamics software ANSYS Fluent,the boundary conditions are embedded by the C language UDF interpreted program is interpreted with Fluent software interface,and considering the snow erosion and deposition on walls,the numerical calculation model was established to simulate the wind-induced snow drifting in the paper.Firstly through simulating the three-dimensional numerical model's snow distribution around a cube,the key technology and parameters of the numerical wind tunnel were discussed.And the feasibility and effectiveness of the numerical model is verified by compared with the measured results.It shows that three equations klk--? turbulence model has the more excellent simulation results.Based on this,regarding the the wind speed,wind direction and geomorphic types as analysis parameters,the wind-induced snow drifting effect of folding reticulated shell structure were simulated.It analyzed the law of the air and snow coupling field after solving the flow field,and obtained the wind-induced snow distribution coefficient,which may provide reference basis for the wind and snow resistance design of similar structures.The results indicate that the flow around the folding reticulated shell with complex shape is even disorder,the sustaining action of the lower wind speed is the worst condition,and the snow erosion and deposition distribute at different area because of the influence of the wind direction,generally showing rules of erosion primarily and local deposition on leeward.The snow load change of same zone caused by the changes of wind direction is very crucial in the wind and snow resistance design of such snow load sensitive structures.In addition,the snow deposition coefficient of the structure surface has a negative correlation with the open degree of four kinds of landscapes.