Research On Wind-Induced Snow Distribution Characteristics Of Building Roofs Using Wind Tunnel Test And Numerical Simulation

The natural disasters caused by snowdrift were introduced, and the relevant research literature was classified and reviewed. The basic theories of the blowing snow were summarized, and a brief analysis was made as well. For several common building structural roofs, studies were carried out to find the wind-induced snow distribution characteristics on the roofs through numerical simulation and wind tunnel test. The main contents are as following:1. Based on the Euler-Euler two-phase mixture model combining with the k-ω turbulence model modified by Wilcox, a numerical simulation analysis program Snow2D was developed. In order to consider the influence of snow deposition on flow in the simulation, the computational domain boundaries used the adaptive deformation technique according to snow-depth changes. Some of the newer numerical methods were applied in the program to improve the robustness of the calculation process, and the program was also validated.2. The Snow2D was adopted to carry out the numerical simulation on the snow distribution caused by wind on a typical stepped roof and two gabled roofs. The flow characteristics around the roofs were analyzed. The snow-depth coefficient and the time history of snow distribution on the roofs were gained. The influences of different inflow velocity ratio on snow distribution on the roofs were analyzed.3. Based on the Lagrange stochastic model and Snow2D single-phase flow pattern, the simulation analysis program for the motion of snow particles caused by wind was developed. By means of PDF random sampling, the Monte Carlo process of the granule stochastic motion was simulated. An optimizing search algorithm of particle-locating was introduced. The influences of different sizes and different wind velocity on snow particles motion were investigated, and then the simulation was made on the snow distribution on a typical stepped roof. The snow efficiency on the roof was surveyed and the time history of the snow distribution on the roof was obtained.4. From the perspective of geometry, kinematics and dynamics, the similarity law which should be realized by wind tunnel test model of snowdrift was analyzed and the choice of the main similarity parameters was discussed.5. The fine quartz sand was adopted as the model of snow grains, and the wind tunnel test was carried out to investigate the snow distribution on a typical stepped roof and two gabled roofs. Firstly, the flow field was measured and the influence of motion granule on flow was briefly analyzed, and then the snow distributions on the roofs under several working conditions were investigated. The snow distribution characteristics under different time, wind velocity and wind angle were measured, and the correlation between the mass flow rate of granule and wind velocity and wind angle was analyzed.6. Based on the numerical simulation results of snow distributions on the typical roofs and the wind tunnel test results, the comprehensive comparison was made with the observation results in the literature, as well as the related provisions in the load codes of building structures were compared and analyzed.