Session: 06-03-04 Fluid-Structure, Multi-body and Wave-body Interaction

Submission Number: 157500

Nonlinear Wave-Body Interactions for Arbitrarily Shaped Body Using 3D Numerical Wave Tank 

In this study, the nonlinear dynamic responses of freely floating body are investigated. This floating body is modeled as a point absorber, a wave energy converter, and is an irregularly shaped cylinder with a water plane area that changes in the vertical direction (a spaceship-like shaped roof). This model was designed to improve the pitch-restoring moment and buoyancy and to increase energy extraction efficiency.

The nonlinear restoring effects and nonlinear wave excitation forces can be significant during the heave or pitch motion due to the irregular shape, but this cannot be taken into account in linear calculations. In nonlinear simulation, the nonlinear hydrostatic restoring force and Froude-Krylov force can be considered. In particular, when the waterplane area changes during simulation, it can cause heave-to-pitch Mathieu instability and heave-to-heave Mathieu instability.

To investigate nonlinear wave-body interaction of this special shaped model, three dimensional fully nonlinear numerical wave tank (FN-NWT) was used. FN-NWT was developed based on potential theory and boundary element method, and it can solve the boundary value problem (BVP) for instantaneous body position and free surface elevation using mixed Eulerian and Lagrangian method every time steps. Therefore, the mesh for the free surface and body are rearranged with each movement, and the BVP is solved at each position. The body displacement considering nonlinear effects are compared with linear calculation results to analyze nonlinear effects.

Presenting Author: Eun-Hong Min Texas A&M University

Presenting Author Biography: Eun-hong Min is a postdoctoral researcher in the Department of Ocean Engineering at Texas A&M University. She received Ph.D. degree in Naval Architecture and Ocean Engineering from Inha University in 2022. She is interested in numerical wave tank, wave-body interaction, internal and nonlinear wave propagation, etc. Dr. Min has published more than 15 journal papers in the field of ocean engineering, and has also presented works at several international conferences, including OMAE.