Optimization study of a catenary mooring system for a spar floating wind turbine based on its hydrodynamic responses

Abstract

In this article, selecting an appropriate mooring system for the spar platform of a wind turbine consisting of chain–cable–chain is investigated based on a meta-heuristic method. A boundary element software is applied to hydrodynamics analysis, and the numerical results are verified by experimental results. According to the characteristics of the experimental mooring system, an appropriate chain is selected for the prototype model, and then a mooring system consisting of chain–cable–chain replaces the chain-based mooring system. Environmental forces have been applied by the conditions of the Caspian Sea. Analysis is done in time domain for irregular wave spectrum of Joint North Sea Wave Project. For the cable in the middle, seven lengths in the range of 30–210 m were considered. The simulations showed that in the cable length of 180 m, the structure exhibits a proper behavior. Also, in order to increase the reliability of the anchor, a portion of the initial chain was reduced and was added to the anchor chain; for this purpose, five different chain lengths from 25 to 65 m have been considered. The results show that for the heave, roll, pitch, and yaw degrees of freedom, the minimum structure oscillation happens in the length of 25 m, finally considering the proper behavior of the structure in the length of 25 m; this length of chain was added to the anchor chain.

Hydrodynamics of Double Tanks in Narrow Environment in Ocean Engineering Based on Boundary Finite Element Method

“…It is related to the approximation method of finite element theory, and is also related to the division technology, shape and performance of the mesh. Generally speaking, the smaller the mesh size of the finite element, the higher the performance of the element, the more accurate the analysis results and the greater the computational cost [7][8].…”

A fully integrated optimization framework for designing a complex geometry offshore wind turbine spar-type floating support structure

“…This, however, leaves open the possibility of subsequent fine tuning of the conceptual design solution obtained through optimization based on hydrodynamic and system-level analyses. By addressing the mooring system in the subsequent detailed design optimization or even in a successive but separate optimization algorithm, the dynamic response of the FOWT system, as well as the mooring line tension itself, can be significantly improved by considering an advanced and more complex optimization problem, in which -apart from various line diameters and lengths -different mooring line arrangements and distribution forms can be utilized, the optimum number of lines within the mooring system and best fairlead position can be elaborated, different mooring types can be used or even mixed within segmented lines, and also clump weights can be incorporated (Tafazzoli et al, 2020;Barbanti et al, 2019;Men et al, 2019;Chen et al, 2017).…”

Flow Discharge Prediction Study Using a CFD-Based Numerical Model and Gene Expression Programming

“…The U.S. Bureau of Reclamation, USBR, (1987) performed detailed laboratory experiments to investigate the behavior of water flow over a spillway, which resulted in the development and publication of spillway design manuals [8]. Physical studies have a number of problems, including high construction costs, the considerable time required for development and testing, and the presence of errors in results due to scaling effects [9][10][11]. The available computing capacity and algorithm improvements helped in finding solutions for a variety of problems, such as flow over the spillway.…”