Hydrodynamic characteristics of the modified V-shaped Semi-floating offshore wind turbine with heave plates

Abstract

In recent years, there is a great need to develop offshore wind energy on a global scale due to the greenhouse effect and energy crisis. Great efforts have been devoted to developing a reliable floating offshore wind energy technology to take advantage of the large amount of wind energy resources that exist in deep water. In this paper, a novel concept of a floating offshore wind turbine (FOWT), namely, the modified V-shaped semi-floating with heave plate, is proposed, and its hydrodynamic characteristics are studied. A numerical model based on ANSYS/AQWA is used to investigate the dynamic motion, response characteristics and mooring performance of the new concept. Moreover, the response amplitude operators (RAOs) of the different response quantities are also elaborated. A comparative study of the dynamic response of the different response quantities of the modified V-shape and original V-shaped semi-floating is carried out for operational environmental conditions. It is found that the modified V-shape semi-floating shows relatively better performance in platform motion and mooring line response.

Stability and performance analysis of hybrid braceless semisubmersible platform installed in real seas

“…Although, the RAOs follow a similar pattern for both the directions and intersect with each other several times which signifies fair agreement between them and will be responded in similar way. However, the present numerical model has shown a quite a similar RAO's at both the directions with the pervious study done by Shi et al (2019), which signifies a good agreement between the models.…”

“…In this work, the calculation was made in Orcaflex (Orcina, 2018) with a series of regular waves which were propagating at −180° towards the platform. Figure 3a and b show the comparison of RAOs in the heave and pitch directions for the semisubmersibles taken earlier numerical study by Shi et al (2019), experimental study Ohta et al (2013) and the present study. However, the study done by Ohta et al (2013) had studied experimentally on larger and heavier platform supporting 7 MW turbine.…”

“…The side columns are used to provide restoring stiffness to prevent capsizing. This semisubmersible model was conceptualized by Karimirad and Michailides (2015) is chosen as the base configuration and can be called as Classical Platform (CP) while Shi et al (2019) has modified the classical V-shaped semisubmersible by comprising three heave plates of 15 m diameter and 0.01 m thickness attached to the base configuration, that is, one at the bottom of each column which can be called as Modified Platform (MP) and further inclusion of two flap type WEC to the modified V-shaped semisubmersible can be called as the Hybrid Platform (HP) here (Figure 1). The properties of the three alternative designs of the V-shaped semi-submersible platforms are mentioned in Table 1.…”

“…Based on the above discussion and need, the aim of the present study is to develop a new hybrid platform and to evaluate the improvements in performances after adding WEC to the base platform. This new hybrid platform is developed after combining two novel concepts provided by two different researchers which are (i) braceless V-shaped FOWT semisubmersible platform of Shi et al (2019) and (ii) Semisubmersible Flap Combination (SFC) type of WEC of Luan et al (2014). The environmental condition is considered from the real sea data provided by Stewart et al (2016).…”

“…PropertiesDesign parameters of V-shaped semisubmersibles Classical (CP)(Karimirad and Michailides, 2015) Modified (MP)(Shi et al, 2019) Hybrid (HP) (Present Study, Figure1)platform. The clump mass is positioned 82 m from the fairlead of each mooring line.…”