The approximate formulas for the natural frequency of bridge piers with shallow foundation, pile foundation and sunk shaft foundation were derived by the RayleighMethod.
采用瑞利法，导出了计算浅平基桥墩、桩基桥墩及沉井基础桥墩基频的近似公式。
2
Then the relationship among vibration frequency of the plate in water and that in vacuo and the Nondimensionalized Added Virtual Mass Incremental (NAVMI) is obtain by utilizing Rayleighmethod.
进而应用瑞利方法得到了薄板水中振动频率与真空中振动频率、无量纲附加虚质量增量之间的关系。
3
But this partial differential equation can not be directly integral, so usually use Navier method, Rayleigh Ritz method and finite difference method and other methods.