Numerical Simulation And Analysis Of High-Speed Railway Noise Barrier Aerodynamic Pressure

The Beijing-Shanghai high-speed railway, as an important project of "long-term railway network plan", represents a total length of 1,318 km. It is designed according to a top speed of 350 km per hour for the whole way, then lasts only 5 hours for a direct arrival from Beijing to Shanghai. While the more serious problem of noise pollution will be encountered with the elevation of speed. The actual technology of noise barriers for urban roads can not satisfies the requirements of Beijing-Shanghai high-speed railway. According to the experiments, the actual sound barriers can withstand the speed of trains up to 200 kilometers per hour without trouble. With the speed higher than 250 kilometers per hour, it appears the significant vibration in noise barriers. To ensure the safe work of noise barriers'structures for the trains in high speed circulation, it needs not only the good properties for sound absorption and noise reduction, but also the dynamic performance for structural requirements.The present paper focus on the research and numerical simulation of dynamic air pressure acted on the noise barriers for high speed trains. Background of the research is the major project of Chinese Ministry of Railway, "Experimental Research on technical measurements for the dynamic air actions on noise barriers of Beijing-Shanghai railway". The work is based on the fundemental theories of computational fluid mechanics (CFD), by means of the platforms of GAB IT for geometrical modeling and FLUENT for analysis.The three-dimensional model for the state of train totally in the sound barrier is built first. Then studies are made on mesh of the model, the model of turbulence, boundariy conditions and the setting up and selection of the involved parameters. By means of the computational analysis, distribution of the pressure field, velocity field, lines of the flow trace, dynamic air pressure in the flow are obtained. The results are compared with the experimental measurements to justify correctness of the simulation results. Then the effective pressure supported by the sound barriers are calculated for several different working conditions of the train and sound barriers. And the empirical formulas are concluded for the loading properties and maximum effective pressure of the sound barriers under different working conditions. Results of the computational research represent the important referential values and practical purpose for structural safety of the sound barriers for high speed trains.