Study on Array Floating Platform for Wind Energy and Marine Space Optimization

Abstract

The concept of multiline anchor, whose application is mainly considered in water depths beyond 100 m and analyzed only by numerical simulation, has been discussed for half a decade, yet previous studies have not conducted the wave basin experiment. Thus, this paper set this concept firstly with a shallow water mooring system designed for a Taiwan offshore water area, where the suitable water depth for floating offshore wind turbine is located from 50 to 100 m, and then conducted a 1:144 scaled model wave basin experiment to validate the results from numerical simulation. In this paper, the numerical model simulated and analyzed three identical DeepCwind OC4 semi-submersible platforms equipped with NREL 5MW wind turbines in OrcaFlex and the experiment carried out by using three 1:144 scaled semi-submersible platforms with equivalent disks which simulated different operations of wind thrusts. To consider the possible influence of the wake effect, the minimum turbines spacing was set at 750 m in a full scaled model and the length of mooring lines was redesigned according to the catenary theory. This paper utilized OrcaWave to calculate hydrodynamic parameters and input it into OrcaFlex to simulate the line tension and the three degrees of freedom (surge, heave, and pitch) of the platforms under regular and irregular wave tests, and coordinate with scaled model tests carried out in Tainan Hydraulics Laboratory (THL). In addition to the reduction in the number of anchors, the concept of multiline anchor was also discussed in this study for the spatial configuration of offshore wind farms. It shows that the wind farm composed of three floating wind turbines can reduce the ocean space by roughly 24% compared to that with a single-line anchor. According to the comparison of numerical and experimental results, this study finally optimized the mooring lines by changing the diameter to increase the stability and the threshold of Minimum Breaking Load (MBL) and proposed a multiline anchor configuration for shallow offshore water area in Taiwan based on the results obtained.

Novel Deep-Water Tidal Meter for Offshore Aquaculture Infrastructures

“…The ocean surface is seen as a succession of irregularly distributed peaks and valleys. In the literature, researchers have described ocean waves in terms of their regularity [ 20 ]. For example, purely irregular ocean waves are produced by unusual events, such as submarines, earthquakes, tsunamis or objects falling into the ocean (e.g., meteorites).…”

Integer Arithmetic Algorithm for Fundamental Frequency Identification of Oceanic Currents

“…To achieve this, it is necessary to make considerations that have been validated in the oceanographic literature. It is known that the ocean surface is composed of a succession of maxima and minima with an irregular distribution in time, although it is described in terms of its temporal regularity [ 18 ]. Furthermore, regardless of depth or weather event, waves can be described using the Fourier model [ 19 ].…”

Numerical Assessment of a Tension-Leg Platform Wind Turbine in Intermediate Water Using the Smoothed Particle Hydrodynamics Method

“…They are based on the TLP system, a preferred solution in the offshore oil sector and their performance is well known; they mainly use vertical tendons to constrain motion along the vertical axis, and can also provide surge constraints at the cost of certain lateral displacements [5]. Moreover, in view Energies 2022, 15, 3993 2 of 23 of the fact that many devices work together (farms), secondary mooring systems can be used to keep the station horizontal and provide redundancy to the overall system [6]. As a fully complementary concept, for the spar-type floating wind turbine (SFWT), there is no noticeable transition from tower to float (spar), and the design and construction of the floating tower should be carried out seamlessly.…”