Effect of structural flexibility and geometry on the hydrodynamic force of vertical columns under dam-break flow

Abstract

Past investigations of the hydrodynamic forces on vertical columns have generally been based on rigid structure assumptions. The effects of structural flexibility and geometry characteristics on the hydrodynamic force distribution are not well understood. In this study, fluid-structure interaction models are developed for numerical analyses. This modeling technique is verified with an experimental test in the literature using both circular and rectangular cross-sections. A series of material elasticities that present structural properties ranging from rigid to flexible is then used to conduct analyses. This finding indicates that an increase in structural flexibility can decrease the impact force to some extent, but this effect is limited. A concrete bridge pier with fluid flow impact can be considered rigid when it is fixed at the bottom. After that, the effects of the initial downstream water height and the width of water tank on the hydrodynamic force are thoroughly investigated. The results demonstrate that the increase in the downstream water height with a constant upstream water height corresponds to a decreased force. Moreover, the vertical column results in a blockage effect on the fluid flow. The greater the blockage effect, the higher the hydrodynamic force. The blockage effect from the vertical column can be neglected when the tank width is greater than eight times the structural cross-section diameter.

Keywords

hydrodynamic force / structural flexibility / material elasticity / initial downstream water height / blockage effect / dam-break flow

Funding

National Natural Science Foundation of China(52222804)

National Natural Science Foundation of China(U21A20154)