Natural frequency analysis of fluid-conveying pipes in the ADINA system

In this paper we present analysis and numerical simulations for the natural frequency of pipes conveying fluid in the ADINA system. The slender pipe structures are modelled as shells and the fluid flows are supposed to be three-dimensional (3D) and incompressible. The fluid and structural models are mechanically coupled on their interface through slip and displacement conditions. Several numerical examples for pipes shaped as different configurations show that the natural frequencies obtained based on ADINA codes are generally lower than those predicted by analytical or dynamic stiffness methods. In particular, for curved pipes conveying fluid with relatively high flow velocity, it is found that the evolution trend of natural frequencies with increasing flow velocity is similar as that predicted by the inextensible theory for curved pipes conveying fluid.