Abstract: Two types of U-shape thin-wall aqueduct models with considering the action of fluid were established according to the potential-based fluid theory and Westergaard theory respectively. With these two models, modal analysis of the aqueduct was conducted, and the effects of water depth on the modal results were also analyzed. Comparing modal results of between these two models, it was found that: (1) the natural frequencies of aqueduct decrease with the increase of water depth; (2) the modal results of Westergaard model are lower than these of potential-based fluid model; moreover, (3) the effects of water depth on the natural frequencies corresponding to the same mode shapes are also different in these two models. On the basis of the comprehensive results comparisons and analysis, an improved Westergaard model (iWestergaard model) was proposed, results showed that the results of i Westergaard model are agree well with these of potential-based fluid model.

Key words: vibration and wave, u-shape thin-wall aqueduct, potential-based fluid model, Westergaard model, i Westergaard model, dynamic characteristics

摘要： 基于势流体理论和Westergaard理论建立两种考虑水体作用的U型薄壁渡槽有限元模型。在两种模型的基础上做模态分析，得到了不同水深下的U形薄壁渡槽的振动特性。对比分析两种模型不同水深下的模态计算结果，得到了：（1）随水深增加，渡槽结构固有频率降低；（2）Westergaard模型计算结果低于势流模型；（3）水深对同一振型频率的影响程度在两种模型中也是不同。在结果对比分析的基础上，提出一种改进的Westergaard模型（iWestergaard模型），结果显示改进的Westergaard模型结果与势流结果吻合的很好。

关键词: 振动与波, U形薄壁渡槽, 势流模型, Westergard模型, i Westergard模型, 振动特性