Study On Wind Characteristics Of V And U-shaped Mountain Canyon Bridge Site

The wind field characteristics of the canyon bridge site area are complex,but the current research on the wind characteristics of the specific mountain terrain bridge site is not sufficient.In order to provide a basis for the wind resistance design of the large-span bridge in the mountainous area,it is necessary to conduct a special study on the wind field characteristics of the typical terrain.This paper takes the U-shaped and V-shaped canyons of typical mountainous terrain as the research object.Firstly,the elevation points of the U-shaped and V-shaped bridge sites are extracted respectively,and a three-dimensional terrain grid is established.Three turbulence models are used to conduct three-dimensional terrain based on the actual bridge site.Numerical calculations analyze the distribution of basic wind characteristics in the canyon bridge site area;then compare and analyze with wind tunnel test data to verify the reliability of the numerical wind tunnel in the wind field study of complex terrain bridge sites,and select the optimal model;,To study the influence of the three parameters of mountain height,included angle and width on the wind characteristics of U-shaped and V-shaped canyons,obtain the flow field distribution mechanism and wind field change rules of U-shaped and V-shaped canyons,and compare and analyze two typical canyon winds.Similarities and differences in characteristics and their distribution laws.The research content of this article provides references for wind-resistant design of large-span bridges in typical mountainous terrain.(1)In order to select the best turbulence model in the canyon terrain calculation,the actual three-dimensional terrain models of U and V-shaped typical bridge sites were established using Rhino software and Gambit respectively,and Realizable k-ε,The three turbulence models of RNG k-ε and SST k-ω were carried out to numerically simulate the wind characteristics,and the difference between the basic wind characteristic parameters and the general wind characteristic parameters in the mountainous bridge site area was obtained,and the factors that had a greater impact on the bridge site wind field were clarified.Similar to terrain parameters,a turbulence model that is more suitable for canyon terrain calculations is selected.And through the comparison with the wind tunnel test data,the reliability of the numerical simulation is verified.(2)In order to obtain the distribution law of the wind field in the canyon with the change of terrain parameters,the influence of the height and angle parameter changes on the wind characteristics of the V-shaped canyon,and the influence of the changes of height and width parameters on the wind characteristics of the U-shaped canyon are respectively considered.Based on the three-dimensional real terrain model of the canyon,numerical simulation is used to analyze the change law of wind characteristics,and the distribution law of the wind field in the canyon with the change of terrain parameters is obtained,and the variation range of the gradient wind height is given,which shows the wind field more intuitively.The changes caused by flowing into the canyon through the mouth of the canyon,and the function model of wind speed changing with the height and angle of the canyon is fitted.(3)In order to further compare the wind parameters of the bridge site with two typical topography of U-shaped and V-shaped canyons,compare and analyze the actual topography of the U-shaped and V-shaped canyons and the numerical wind tunnel research results under different topographic parameters.The similarities and differences of the flow field distribution mechanism and wind field change law of the two terrains,as well as the similarities and differences of the function model of the wind speed with the canyon height and the angle.