Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on load characteristics of floating VAWT considering coupling of aerodynamics andhydrodynamics
Weiqin Liu1, Wenping Luo1*, Ye Li2, Ding Zhang3
1. Departments of Ocean Engineering, School of Naval Architecture, Ocean and Energy Power Engineering, Wuhan University of Technology,Wuhan, Hubei, China
2. Laboratory of Multiple Function Towing Tank, State Key Laboratory of Ocean Engineering, Shanghai Jiaotong University, Shanghai, China
3. Marine design and research Institute of China, Shanghai, China*Corresponding Author: Wenping Luo

maintenance, makes center of gravity of the structure is lower, moresuitable for waves on the sea environment.

ABSTRACTFOWT consists of turbines and floating foundations, many scholars
have done independent researches of load and response on these twoparts. The calculation methods of turbines aerodynamic performance
mainly include Blade Element Momentum(BEM), Computational Fluid
Dynamics(CFD) and Vortex Lattice Method(VLM), and methods forcalculating hydraulic performance of platform mainly include 3D
potential flow theory and CFD. Ding et al. (2016) studied the influenceof pitch Angle on aerodynamic performance of HAWT based on BEM.
Srensen et al. (2002) based on RANS equation, k-ω SST turbulencemodel was used to simulate aerodynamic performance of turbines atdifferent wind speeds. Overset mesh technique and finite difference
method were used to solve the aerodynamic load of blades, and CFD
was found to be more accurate than potential flow (Duque et al, 2003).
Luo et al. (2021) studies the load characteristics of a semi-submersible
platform based on three-dimensional potential flow theory. In order toconsider the load difference caused by viscosity, CFD theory was used
to calculate the hydrodynamic performance of DeepCWind platform. It
was found that the viscous flow calculation results were basicallyconsistent with the test and had certain advantages (Tran and Kim,2015). It can be found that CFD is more accurate in the calculation of
aero-hydrodynamic performance, because it is closer to the actual fluidproperties.

Vertical Axial Wind Turbine (VAWT) has advantages to utilize windenergy at vertical wind section and to adapt changeful wind direction sothat VAWT becomes latest wind turbine type for deep-open sea. Inorder to discuss load characteristics of floating VAWT caused bycoupling movement of blade and platform, a deep-sea floating H-type
VAWT is regarded as the research object. A large platform based oncomputational fluid dynamic (CFD) was used to calculate the load ofVAWT in the gas-liquid two-phase flow field, sliding and overset meshwere used to simulate the motion of the rotating blades and platform,
the VOF method was used to accurately capture the position of the freeliquid surface, and the load characteristics of the VAWT were obtainedby combining the multi-grid refining technology. This method wasvalidated by experiment data and used to simulate the load and motionof VAWT under a series of working conditions, and the aerodynamic
and hydrodynamic performance of the floating VAWT and its variation
with wave height and wave length are found by analyzing thesimulation results.

KEY WORDS: VAWT; CFD; Load characteristics; Aerodynamic;
Hydrodynamic; Coupling.

INTRODUCTION

The turbines rotating around the axis produces varying loads under theaction of wind, while the floating foundation is subjected to the actionof waves and produces corresponding movement. There is a strong
coupling relationship between the load generated by the turbines andthe movement of the floating foundation, which affects each other.
Than and Kim. (2016) took the standard 5MW floating HAWT in theOC project as the object, and Dynamic Fluid Body Interaction (DFBI)
is introduced to obtain the time-domain aerodynamic performance ofthe turbines and the time-domain dynamic movement of the platform
under the aero-hydrodynamic coupling. The results showed that thecalculation results of this method were highly accurate. Kvittem et al.
(2012) based on BEM and potential flow theory, the frequency domain
motion response and partial dynamic performance of the 5MW floating
HAWT under the aero-hydrodynamic coupling were analyzed, and it
was found that the platform motion had a certain influence on theThe traditional fossil energy is increasingly scarce in the world, and thesearch for new alternative energy has become the focus of research allover the world. The ocean is vast and the wind energy reserve is moreabundant than the land, so the floating offshore wind turbine (FOWT)
has gradually become a new focus of wind energy development. FOWT
can be divided into horizontal axis wind turbine (HAWT) and verticalaxis wind turbine (VAWT) according to the different directions of therotation axis of the wind wheel in space. VAWT was first proposed by(DARRIEUS, 1931) in the 1930s, but was not further developed due tothe limitations of technology at that time. In recent years, with thedevelopment of wind power gradually to the deepsea area, due to thecomplex and changeable wind environment and high maintenance cost,
VAWT once again return to the public's field of vision, VAWT withoutsteering can take advantage of the wind in all directions, and thegearbox and generator at the bottom of the tower in ease of352