矩型渡槽槽-水耦合体高阶共振特性研究

Research on higher-order resonance characteristics of duct-water coupled components in rectangular aqueduct bridge

建立在小幅晃动假设上的槽水耦合体响应理论解显示,当外加激励为简谐荷载且激振频率为水体奇数阶晃动频率时,槽内水体出现共振现象,响应幅值趋于无穷大。如果此理论解确能代表现实中响应特性,则渡槽减隔震设计中存在槽-水耦合体高阶共振问题。这不但给渡槽减隔震设计增加了难度,也给实际工程带来潜在的风险。因此,通过槽-水耦合体高阶共振特性的CFD仿真分析,对槽-水耦合体高阶共振特性进行概念修正,并得出在渡槽减隔震设计中,几乎不存在槽-水耦合体高阶共振影响,在选择隔震周期时,只需避开一阶水体晃动频率的结论。

Theoretical solution based on the assumption of small amplitude sloshing suggests that the dynamic responses of duct-water coupled components drive to infinite under an excitation of simple harmonic waves of odd frequencies. If this solution reflects the reality, then the higher-order resonance has to be considered in the aqueduct bridge design, which leads to a design difficulty and also bring hidden risks to a practical project. This paper shows the need to modify the conceptions from the theoretical solution of small amplitude sloshing. An analysis on the higher-order resonance of duct-water by using CFD simulation verifies that actually almost no higher-order resonances can occur, and that only the natural sloshing frequency needs be avoided when determine the isolation period in the isolated design of aqueduct bridge.