科研之友
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摘要
Cable towers are an important aerodynamic noise source of long-span bridges. The flow effect of various parts of the cable tower on airflow will cause large aerodynamic noises and thus influence environments. This paper conducted on research on the cross-sectional structure of the cable tower of long-span bridges, built a computational model of aerodynamic noises for cable towers of long-span bridges with original rectangular cross section and improved cross section. The computational fluid dynamics was adopted to analyze the non-steady flow of cable towers, and the numerical value of aerodynamic noises was predicted based on Lighthill's acoustic analogy. Then, acoustic BEM was also adopted to study radiation noises of cable towers in the far-field. Results showed that improved cable tower could reduce the dispersion degree of airflow and weaken Karman Vortex Street. Aerodynamic noises induced by cable towers with improved cross section mainly radiated in a direction perpendicular to airflow, and the directivity of noises was obvious. Sound pressure level (SPL) of aerodynamic noises of cable towers with improved cross section was 4.2 dBA less than that of initial rectangular cross section in the far-field, which showed obvious effect on noise reduction. In the meanwhile, this paper studied the mechanism of main frequency at various parts of cable towers with improved cross section and discussed the reason of noise reduction, whose research achievements could provide design basis for generation mechanism and reduction of aerodynamic noises of cable towers of long-span bridges.
- 出版日期2017-5
- 单位同济大学
