Stochastic dynamic analysis of floating solar structures

Abstract

This thesis investigates the dynamic responses of floating solar platforms under regular and irregular wave conditions using Computational Fluid Dynamics (CFD) models developed in OpenFOAM. Floating Photovoltaic (FPV) systems offer a promising renewable energy solution but face significant hydrodynamic challenges in offshore environments. The study focuses on a gable-slender platform in single- and double-cylinder configurations, validated against wave tank experiments conducted at Queen’s University Belfast. Mesh convergence tests identified Refinement Level 3 as optimal, achieving RMSE as low as 1.02 × 10⁻⁴. The numerical model accurately replicated wave elevations with RMS errors of 0.82% for moderate waves, increasing to 7.36% for steeper waves. Comparative assessments revealed that the CFD model significantly outperformed higher-order potential flow models in capturing nonlinear interactions such as wave run-up and overtopping. For regular waves, single-cylinder heave deviations ranged from 9.18% to 31.42%, while surge force discrepancies rose with wave steepness. Double-cylinder heave deviations peaked at 35.9%, and surge forces deviated up to 42.72% under steep wave conditions, highlighting the difficulty in modelling coupled pitch-roll effects. Under irregular waves (JONSWAP spectrum), uncorrected simulations underestimated wave heights by up to 24%, reduced to 2.8% after gain correction. Spectral deviations in heave and surge responses ranged from 5.14–13.38% and 2.51–14.18%, respectively. The research also examined geometric parameters. Smaller cylinder diameters (0.055 m) yielded better damping, while larger diameters (0.220 m) amplified dynamic forces. Shorter gaps between cylinders (0.25 m) intensified responses, whereas wider gaps (1 m) led to complex flow interactions and higher-order excitations. This work advances the understanding of FPV hydrodynamics and provides validated numerical tools and design insights critical for deploying floating solar systems in marine settings.

Thesis embargoed until 31st July 2026.

Date of Award	Jul 2025
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Tezpur University
Supervisor	Madjid Karimirad (Supervisor), Pauline MacKinnon (Supervisor) & Nabin Sarmah (Supervisor)