The Study Of Atmospheric Flow Field Around Highways Bridge Segment

The dissertation is a part of the National Natural Science Foundation of China named "The research on the effect of highway construction on regional airflow field". Highway construction has played a significant role in promoting the social and regional economic development. However, due to its rapid pace of construction, highway ecological and environmental protection technology and theoretical research lag. It causes the surrounding environment change and destroys the equilibrium of the ecological environment of the region inevitably. After the highways are built, the surrounding flow field is changed and the automobile exhaust emissions and other problems will increase the atmospheric environment pollution in coastal areas. Thus, it’s very significant to do research in highway area flow.At the present time, field measurement, wind tunnel trial, and numerical simulation are the three major research methods of the Wind Engineering. Numerical simulation has low cost, short cycle and high efficiency advantages so it has become a focus for researchers. The paper, based on the basic theory of computational fluid dynamics, and use the most mature commercial CFD software——fluent to simulate the highway environment and to study the distribution of flow flield around the highway bridge segment.The main research content:(1)This paper introduces the basic theory and equation of the method of numerical simulation and determines reasonably applicable closed model and solution methods. The turbulence model use RNG k-ε turbulence model. The numerical simulation use Finite Volume Method(FVM). Use SIMPLE pressure correction algorithm for over-relaxation iterative computing. Use unstructured grid and mesh refinement. The mesh quality is good.(2) This paper writes appropriate boundary conditions programs, then analyzes and summarizes the pressure and flow velocity around highway bridge along height and vertical bridge length direction, and sums up some of the rules and characteristics of flow field around the distribution of highway bridges.(3)This paper considers two factors, the flow rate and geomorphic characteristics, obtaines the variation of the highway bridge section of the flow around and provides a reliable basis for the environmental governance of highway regional air. (4)Summary the research work of this article and put forward some opinion of numerical simulation and put forward further studies on the job.