Abstract
To study complexity distributions of unsteady flow field and aerodynamic noise of a high-speed railway on bridges, an aerodynamic noise model of a railway was obtained. Meanwhile, detailed structures such as 6 bogies, 3 air conditioning units, 1 pantograph fairing, and 1 pantograph were considered. Numerical simulation was conducted to flow fields around the high-speed railway running on the bridge under a crosswind-free environment, with running speed of 350 km/h. Hence, unsteady flow behavior characteristics of the complete high-speed railway were obtained. Numerical simulation was conducted to noises of the railway on the bridge in combination with detached eddy simulation and acoustic analogy theory. Meanwhile, the broadband noise model was used for the quantitative analysis on distribution characteristics of the dipole noise source and quadrupole noise source of the high-speed railway on the bridge. Studied results proved that aerodynamic noise of the railway was caused by eddy shedding and fluid separation. Main noise sources of the high-speed railway include areas such as pantographs, train head streamline, bogies, windshield, and an air conditioning unit. Maximum sound pressure level and average sound pressure level of the high-speed railway on the bridge were 2.7 dBA and 2.3 dBA, respectively, more than those of the high-speed railway on a flat ground. On the bridge, the maximum sound pressure level of the pantograph on the bridge was 3.1 dBA larger than that on the flat ground. In addition, incoming flows of the high-speed railway on the bridge had greater impacts on aerodynamic noises around the railway compared with those of wake flows. Meanwhile, in directions of incoming flows and wake flows, linear relationship was between the sound pressure levels of noise monitoring points which had different distances from the train head nose and the logarithm of the distances.
Highlights
With the high running speed, the aerodynamic noise of the high-speed railway will increase sharply
Complexity results [8, 10,11,12,13,14,15] show that major aerodynamic noise sources of high-speed railways include the pantograph, bogie, nose tip, pilot, train head, train tail, window, door, joint, skirt board, and so on
Sun et al [22, 23] established a three-train high-speed train aerodynamic model, analyzed flow field characteristics at head, carriage joints, tail parts, and other parts of the train, and researched contribution made by different train parts to the aerodynamic noise, wherein the bogie and pantograph were not considered in the model
Summary
With the high running speed, the aerodynamic noise of the high-speed railway will increase sharply. Complexity results [8, 10,11,12,13,14,15] show that major aerodynamic noise sources of high-speed railways include the pantograph, bogie, nose tip, pilot, train head, train tail, window, door, joint, skirt board, and so on. Yamazaki et al [16] conducted the wind tunnel experimental research and field test to a Shinkansen train with the scaling ratio of 1 : 5, finding that joints belong to main noise sources of high-speed railways. Sun et al [22, 23] established a three-train high-speed train aerodynamic model, analyzed flow field characteristics at head, carriage joints, tail parts, and other parts of the train, and researched contribution made by different train parts to the aerodynamic noise, wherein the bogie and pantograph were not considered in the model. The paper established an aerodynamic model of a high-speed railway and an aerodynamic noise model to analyze unsteady aerodynamic flow of the railway, conducted quantitative analysis on dipole noise sources and quadrupole noise sources of the railway on the bridge in combination with the broadband noise source model, and researched far-field noise characteristics of the railway in combination with DES and FW-H equations, obtaining aerodynamic flow behavior characteristics of the high-speed railway on the bridge, far-field aerodynamic noise distribution of the railway, aerodynamic noise radiation characteristics on the bridge, and so on
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