Fluid-Structure Interaction: Impact of Reservoir Simulation Approach Considering Far-Field Boundary Condition in Dam Seismic Response

Abstract

Given the vitality of dams to life and the catastrophe caused by their failure, an adequate safety margin must be considered while designing for permanent and transient loads. Neglecting the transient loads in design make the dam structure vulnerable to damage; consequently, the earthquake load is crucial as a transient dynamic load. The horizontal component of an earthquake causes acoustic waves to exert hydrodynamic pressure on the dam's upstream face in addition to hydrostatic pressure. This study aims to assess the dynamic response of a dam using Lagrangian-Lagrangian and Lagrangian-Eulerian modeling approaches for a solidliquid interaction. To this end, as a case study, time-domain analysis is carried out using ANSYS to determine the PINE FLAT dam response subjected to the horizontal component of the TAFT ground motion. The results indicate that considering the following points, the dam's dynamic responses in both approaches are almost identical. In order to absorb the scattered acoustic waves in the Eulerian reservoir, a condition involving a particular boundary element at the far field with a specific geometry must be provided. Also, the length-toheight ratio of the reservoir must not be less than a specific value in the Lagrangian fluid to minimize the effect of propagated acoustic wave reverberation.

Keywords

• Fluid-structure interaction
• Hydrodynamic pressure
• Concrete dam
• Added mass
• Dam reservoir interaction