Numerical study of floating oscillating water column WECs using lattice boltzmann method

Guo, Baoming 2025. Numerical study of floating oscillating water column WECs using lattice boltzmann method. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This study is to develop a robust lattice Boltzmann method (LBM)-based computational framework for simulating the dynamics of the floating oscillating water column (OWC) wave energy converters (WECs). To simulate the complex air-water-solid interactions involving partially submerged and freely moving bodies for the OWC devices, the numerical framework integrates the interpolated bounce-back scheme for fluid-structure interaction (FSI) with the volume-of-fluid (VOF) method for free surface capturing. The developed model is then applied to conduct a wide range of numerical simulations to investigate the hydrodynamic performance and power extraction characteristics of both two�and three-dimensional heave-only OWCs. The modelling results confirm the effectiveness of the proposed two-stage approach, whereby the potential-flow model facilitates rapid and extensive parametric exploration to identify optimal design parameters, and the subsequent LBM simulations provide more physically realistic predictions of the power output by incorporating viscous and nonlinear effects that are inherently absent in the inviscid theoretical model, which otherwise tends to overpredict performance. The numerical results also reveal that the heave-only OWC system behaves as a coupled mass-damping-stiffness oscillator with two natural frequencies: one associated with internal fluid motion and the other with the heave resonance of the floating structure. In the elastically constrained configuration, this coupling produces a broader valuable frequency bandwidth than the fixed or freely floating cases. Overall, the developed LBM framework, complemented by theoretical modelling, proves capable of accurately capturing complex air-water-solid interactions and provides new physical insights into the hydrodynamic behavior and power extraction efficiency of floating OWCs under realistic sea states.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1. Lattice Boltzmann Method (LBM) 2. Floating OWC 3. Hydrodynamic efficiency 4. Free-surface flows 5. Fluid-structure interaction 6. Wave energy conversion
Date of First Compliant Deposit:	19 December 2025
Last Modified:	19 Dec 2025 10:41
URI:	https://orca.cardiff.ac.uk/id/eprint/183317

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