CFD evaluation of erosion rate around a bridge near a sand dune

[摘要] This study performs a series of simulations through solving the Navier-Stokes equations and the RNG k- turbulence model to investigate the wind erosion rates around a bridge in a desert area with sand dunes. The digital elevation model of sand dunes and the bridge model are obtained respectively from hypsographic map and construction drawings. Through combining them into the CFD software of Fluent the simulation zone was formed. The data of wind speed obtained from field observation is fitted into a logarithm format, which was imported into Fluent model as a inlet wind speed condition. Then, the effect of Dun-Go railway on wind-blown sand movement of the neighbouring environment is simulated. The results exhibit that affected by both the sand dune and bridge, the flow field is in a complex condition. It is also shown that the bridge in upstream of the sand dune will not increase the sand transport rate intensively, but change both wind velocity gradient and turbulence kinetic energy over surface of sand dune. On the other hand, when the bridge is built downstream the sand dune, simulation results show that sand deposition rate would be decreased in reference region downstream the pier.

[发布机构] Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, No.222, South Tianshui Road, Lanzhou, Gansu; 730000, China^1

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] Complex condition;Construction drawings;Digital elevation model;Field observations;Sand deposition;Sand transport rate;Turbulence kinetic energy;Wind-blown sands