Work

Study on change mechanism of hydrodynamic force on circular pier with excitation frequency near free surface under earthquake

Year: 2025

Type: article

Abstract: Many studies show that the hydrodynamic force on the unit height of the deep-water pier near free surface under earthquakes changes with excitation frequency, but no investigation has been conducted to uncover the change mechanism behind this phenomenon. Based on radiation wave theory, the hydrodynamic force is decomposed into the radiation wave force and the inertial force for the first time. It's found that the added mass coefficient of radiation wave force changes with excitation frequency, which is responsible for the change of hydrodynamic force with excitation frequency. When excitation frequency is smaller, the increment of the radiation wave force is larger than the decrease of the inertial force, resulting the increase of hydrodynamic force when getting closer to the free surface; when excitation frequency is larger, the increment of radiation wave force is ignorable and the decrease of inertial force is larger, resulting the decrease of hydrodynamic force when getting closer to the free surface. Further investigation in flow field reveals that when excitation frequency is smaller, the flow field near free surface is dominated by wave flow field; when excitation frequency is larger, the flow field is dominated by oscillating flow.

Source: Ocean Engineering

DOI: 10.1016/j.oceaneng.2025.122509