Research On Snow Distribution Of Cubic Model And Step Roof Model Based On CFD Method

Snowdrift formation on the roof and around buildings can be a major problem in snowy and windy areas.The accurate prediction of snow distributions on the roof of buildings becomes an important factor in designing structures in the snowy regions.The accumulation of snow on the roof is complicated due to the wind action(e.g.,wind velocity,turbulence intensity,and wind direction),temperature,humidity,the geometry of roofs,and the properties of snow.Therefore,it is necessary to predict the uneven distribution of snow cover on the roofs of buildings with high accuracy.In recent decades,the computational fluid dynamics(CFD)has become a popular technique with the dramatically increasing in computational power together with advances in computer software to more accurately simulate the snowdrift problems.The CFD based numerical simulation is expected to be a reliable and feasible design tool to predict the snow distribution on the roof of buildings.The numerical simulation of the uneven distribution of snow covers on the cubic model roof and stepped flat roof is carried out.Because stepped flat roofs are very sensitive to snow loads,the uneven distribution of snow almost occurs under the combined action of wind and snow and the collapse of the step flat roof structures are frequently occurring in the snow disaster.Stepped flat roofs are broadly used in civil construction and industrial buildings.At present,the research on the distribution of snow on the cubic model roof and the stepped flat roof model does not consider the influence of different factors.The uneven distribution of snow on the two roofs and the causes of the formation are analyzed.This dissertation conducts the following studies.(1)The numerical simulation and field measurement on the cubic model roof are carried out to analyze the unbalanced snow distribution.The rationality of the numerical simulation method based on CFD is verified by comparing the snow load on the cubic model roof with that of the experimental results.(2)The cube and the stepped flat roof are modeled by Gambit,and then the numerical simulation based on the mixture multiphase flow model provided by Fluent was carried out to analyze the uneven distribution of snow under the different computational domain sizes,different wind speeds,and different snow densities.Through the analysis of numerical simulations,snow distribution under different computational domain sizes,different wind speeds and different snow densities were clarified by comparing the snow distribution coefficients on the roof of models.