Session: 09-04-02: Floating Solar Energy 2

Paper Number: 127917

127917 - Analysis of Nonlinear Hydrodynamic Properties of Shallow-Draft Floating Photovoltaic Structure 

In recent years, the demand for floating solar farms has increased rapidly. Currently, floating photovoltaic (PV) solutions are predominantly developed and employed in inland freshwater environments. Constrained by the scarcity of freshwater resources and the growing demand for efficient power generation, there is a rising focus on the advancement of offshore floating PV systems. Most floating PV structures are generally characterized by light-weight, large-span, shallow-draft, which leads to differences in dynamic characteristics with traditional marine floating structures and requires systematic evaluation and research.

This study analyzes the hydrodynamic characteristics of a frame-type photovoltaic structure with multiple horizontal cylinders distributed in a decentralized manner to jointly provide buoyancy. Considering the phenomenon of drastic changes in the cylinder’s instantaneous wet surface, which is very easily caused by the shallow draft and light weight of the structure, this study establishes a numerical method for calculating the dynamic effects caused by the instantaneous wet surface. The validation results indicate the established numerical model has a good prediction of the wet surface change induced nonlinearities including nonlinear hydrostatic restoring forces and nonlinear FK forces.

Based on the numerical method above, the following studies were carried out: 1) free decay test of a single float under hydrostatic conditions. 2) analysis of the force characteristics of a fixed single float under wave conditions. 3) an analysis of the hydrodynamic characteristics of the entire structure in unrestricted motion under wave conditions. The result shows that the nonlinear hydrostatic restoring force and nonlinear FK force have significant differences compared to the linear restoring force and linear FK force. By comparing the response results from these studies with the linear response results based on the average wetted surface, the necessity to take into account instantaneous wetted surface variations is illustrated, which may result in specific dynamic response phenomena such as octave resonance response.

Presenting Author: Hangyu Cao Ocean University of China

Presenting Author Biography: 1. 2021/06– Now, Department of Ocean Engineering, Ocean University of China (OUC), Ph.D. student.
2. 2019/06– 2021/06, Department of Ocean Engineering, Ocean University of China (OUC), Master student.
3. 2015/06– 2019/06, Department of Ocean Engineering, Ocean University of China (OUC), Bachelor Degree.

Authors:

Hangyu Cao Ocean University of China
Junfeng Du Ocean University of China
Shujie Zhao Ocean University of China
Deqing Zhang Ocean University of China
Anteng Chang Ocean University of China