Session: 09-01-12 Wind Energy: System Optimization 1

Paper Number: 124171

124171 - Numerical Study on Design Optimization of Tension Leg Platform for Fowt Based on Surrogate Model and Multi-Objective Evolutionary Algorithm 

Recently, various studies have been conducted on floating offshore wind turbines (FOWT) as a future eco-friendly energy source. Platforms supporting wind turbines were investigated in various types, such as semi-submersible, spar, tension-leg platform (TLP), and barge type. Among them, TLP-type FOWT has the advantages of small motion response and required area compared to other platforms. However, TLP-type FOWT can induce excessive tendon load including nonlinear response and incur high costs in manufacturing and installation. Therefore, it is necessary to design a TLP-type FOWT that takes into account multiple purposes. In this study, a systematic numerical study on design optimization was performed for the TLP type FOWT. The target platform was selected with the design consisting of a central circular column and three offset square columns with the connecting pontoon. First, the input design variables were selected considering the geometrical shape as well as the mooring lines. Next, the design of the experiment (DOE) was performed to determine the variance level of the input variables, and the amount of sample points has been generated. In the present research, the fully coupling wind-current-wave hydrodynamic analysis under extreme environmental conditions was conducted by using the commercial software WADAM and the open-source code OpenFAST. Using the simulation results, a surrogate model based on the response surface method (RSM) was built to predict the manufacturing cost, motion response of the platform and tendon loads. Then, the fitness of the surrogate model was evaluated by using the analysis of variance (ANOVA) method. Finally, the optimal design for multiple objective functions was found using the NSGA-II optimization algorithm. Afterward, the motion response and tendon load under extreme conditions were verified for the optimal TLP type FOWT by comparing with the CFD results.

Presenting Author: Hyo-Jin Park Seoul national University

Presenting Author Biography: PhD Candidate 2021.09 ~ Present Seoul National University, Korea
BSc 2021.09 Seoul National University, Korea

Authors:

Hyo-Jin Park Seoul national University
Zhenhao Song Seoul National University
Bo Woo Nam Seoul National University
Yoon-Jin Ha Korea Research Institute of Ships & Ocean engineering (KRISO)
Kyong-Hwan Kim Korea Research Institute of Ships & Ocean engineering (KRISO)