The Spar Platform: A Design That Transformed Deepwater Development

2020 ◽  
Vol 72 (09) ◽  
pp. 76-77
Author(s):  
Chris Carpenter
Keyword(s):  
Spar Platform

Power production of the hybrid Wavestar point absorber mounted around the Hywind spar platform and its dynamic response

2021 ◽  
Vol 13 (3) ◽  
pp. 033308
Author(s):  
Hamid Reza Ghafari ◽  
Atefeh Neisi ◽  
Hassan Ghassemi ◽  
Mehdi Iranmanesh
Keyword(s):  
Dynamic Response ◽  
Power Production ◽  
Spar Platform ◽  
Point Absorber

Study on Nonlinear Motion Behavior of Coupled Heave-Pitch for the Classic Spar Platform Based on AQWA

2012 ◽  
Vol 170-173 ◽  
pp. 2170-2174 ◽  
Author(s):  
Song Sang ◽  
Yuan Zhou ◽  
Xue Liang Jiang
Keyword(s):  
Incident Wave ◽  
Wave Amplitude ◽  
Wave Period ◽  
Critical Periods ◽  
Spar Platform ◽  
Natural Period ◽  
Nonlinear Motion ◽  
Motion Characteristic ◽  
Instability Parameter ◽  
Motion Behavior

This paper used AQWA software to research the nonlinear motion characteristic of heave-pitch coupling of classical Spar platform in regular waves. With classic Spar platform as an example, the wave amplitude and periodic changes’ effect to the nonlinear motion behavior of coupled heave-pitch is researched. After calculation, the critical periods corresponding to the different incident wave amplitude are obtained, based which, gets the instability parameter domain of coupling resonance of platform in the wave period-amplitude plane. The results in this paper show that the heave-pitch coupled resonance of platform depends on the wave amplitude and the ratio of the natural period of heave and pitch, and the incident wave period.

Short-Term Extreme Motions of a Spar Floating Wind Turbine Estimated Through a 1:30 At-Sea Experiment

2018 ◽  
Author(s):  
Carlo Ruzzo ◽  
Nilanjan Saha ◽  
Felice Arena
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Extreme Values ◽  
Model Structure ◽  
Ocean Engineering ◽  
Short Term ◽  
Spar Platform ◽  
Six Degrees Of Freedom ◽  
Floating Wind Turbine ◽  
Scale Models

The present paper deals with the estimation of the short-term extreme motions of a spar floating wind turbine in parked rotor conditions, through a 1:30 at-sea experiment, carried out at the Natural Ocean Engineering Laboratory (NOEL) of Reggio Calabria (Italy). Thanks to some favorable local environmental conditions of the site, several wind-generated sea states with relatively low significant wave height (Hs < 0.50 m) have been collected during the experiment. These sea states are scale models of ocean storms, which are relevant hydrodynamic design conditions for the spar platform. The 30-minutes extreme values of the model structure motions have been estimated for all the six degrees of freedom, using the Weibull Tail Method (WTM), and the results obtained are presented in the paper. Such estimations are 1:30 scale models of the 3-hours extreme values of the spar motions in parked rotor conditions and may be directly used for design purposes.

scholarly journals NON-LINEAR DYNAMIC ANALYSIS OF COUPLED SPAR PLATFORM

2013 ◽  
Vol 19 (4) ◽  
pp. 476-491 ◽  
Author(s):  
Mohammed Jameel ◽  
Suhail Ahmad ◽  
A. B. M. Saiful Islam ◽  
Mohd Zamin Zummat
Keyword(s):  
Dynamic Analysis ◽  
Wave Frequency ◽  
Mooring Line ◽  
Wave Loading ◽  
Structural Behaviour ◽  
Offshore Structure ◽  
Spar Platform ◽  
Linear Dynamic ◽  
Long Duration ◽  
Non Linear

Spar platforms are treated as cost-effective and resourceful type of offshore structure in deep water. With increasing depth there are significant changes in its structural behaviour due to coupling of spar hull-mooring line along with radical influence of mooring line damping. So these phenomena should be precisely counted for accurate motion analysis of spar mooring system. In present study, spar platform are configured as a single fully coupled integrated model in ABAQUS/AQUA. Non-linear dynamic analysis in time domain is performed adopting Newmark-β automatic time incrementation technique. Non-linearities due to geometric, loading and boundary conditions are duly considered. Displacement and rotational responses of spar and mooring tensions are obtained during long-duration storm. spar responses get significantly modified and mean position of oscillations gets shifted after longer wave loading. The surge, heave and pitch responses are predominantly excited respectively. The energy contents of PSDs of these responses reduce considerably after long wave loading. Mooring tension responses are significantly different reflecting the damping effect of mooring lines. The pitch response is fairly sensitive to the wave loading duration. After long duration of storm the wave frequency response increases. However, low frequency and wave frequency responses may simultaneously occur due to synchronising sea states.

Research on Collision Mechanism for a Ship Colliding With a Spar Platform

2007 ◽  
Author(s):  
Zhiqiang Hu ◽  
Weicheng Cui ◽  
Longfei Xiao ◽  
Jianmin Yang
Keyword(s):  
Numerical Simulation ◽  
Structural Damage ◽  
Simulation Method ◽  
Hydrodynamic Characteristics ◽  
Spar Platform ◽  
Mooring Lines ◽  
Hull Design ◽  
Truss Spar ◽  
Internal Mechanism ◽  
Double Hull

The collision mechanisms of spar platform haven’t caused so much attention as that of ships in the past, for the short of this kind of collision accidents reported. But this does not mean the impossibility of the collision accident in the future. The research on external mechanism and internal mechanism for a ship colliding with a spar platform is introduced in this paper. A model test is designed to study the external mechanism. The collision scenario is described as a ship colliding with a spar platform moored in 1500 meters water depth. The specifics of the spar’s motions and the tension forces of the mooring lines are gathered, to find the hydrodynamic characteristics in the collision scenario. It is found that the maximal displacements and the maximal pitch angles of the spar platform, and the maximal tension forces of mooring lines are all linearly proportional to the initial velocity of the striking ship basically. Mooring lines play elastic roles in the collision course. The internal mechanism of the ship colliding with the spar platform is achieved by numerical simulation method and the software used is MSC.DYTRAN. A Truss-Spar is taken as the object and a double hull structural design is adopted in the part of hard tank near water surface. The curves of collision characters and the structural damage are obtained. The crashworthiness of the double hull design is verified, through the numerical simulation results.

Spar Platform Installation: Tank Flooding Simulation

2014 ◽  
Author(s):  
Abel Medellin ◽  
Michelle Arango-Turner ◽  
Curtis Fuhr
Keyword(s):  
Hydrostatic Pressure ◽  
Modeling And Simulation ◽  
Time Domain ◽  
Time Interval ◽  
Design Phase ◽  
Time Domain Simulation ◽  
Spar Platform ◽  
Software Suite ◽  
Dynamic Time ◽  
The Time Domain

Spars are towed to installation site horizontally and upended by progressive flooding of tanks. It is common practice to perform a dynamic time domain simulation for a self upending classic spar to determine hydrostatic pressures on compartments. There are many different flooding scenarios that create challenges in modeling and simulation during the design phase. In one particular scenario, the spar upending is initiated by opening valves that allow water to flood into the skirt tank. The skirt tank will progressively fill, based on the differential hydrostatic pressure at valves, and cause the spar to upend. Flooding into keel tanks will commence once respective openings become submerged. Several openings from the skirt tank into the keel tanks reduce the differential pressure experienced in the keel tanks during upending. Simulation of the transfer of water between tanks cannot be modeled with ease using the standard tank flooding options available within the software suite. This particular compartment flooding problem is solved by utilizing a scheme in which the time domain simulation was performed iteratively for a specified time interval. For every iteration the amount of water transferred between the skirt and keel tanks are calculated. The amount of water transferred is calculated using a custom modeling technique. The openings from the skirt tank into the keel tanks are not modeled as a typical hole or valve into a compartment, but the location of these holes are modeled. The amount of water flowing through these openings is determined by the water level in the skirt tank, friction through the opening, and pressure inside the keel tanks. This paper will describe in detail the scheme developed, the tank modeling requirements, and the results obtained.

Sensitivity Analysis of Different Parameters of Taut Mooring System of a Truss Spar

2019 ◽  
Author(s):  
Zhuang Kang ◽  
Rui Chang ◽  
Youwei Kang ◽  
Shanchuan Liu
Keyword(s):  
Design Parameters ◽  
Mooring Line ◽  
Main Body ◽  
Mooring System ◽  
Spar Platform ◽  
Truss Spar Platform ◽  
Hole Position ◽  
Line Force ◽  
Truss Spar ◽  
Nonlinear Solutions

Abstract The taut mooring system is widely used for some advantages, such as smaller mooring radius, lighter total weight and better anti-corrosion performance. In this paper, the taut mooring system of a Truss Spar platform which was taken as the research object was investigated under the condition of 2000 m water depth in South China Sea. Firstly, the main body of the platform was analyzed in frequency domain based on the 3-d potential theory, and then the nonlinear solutions of platform displacement and mooring line force were obtained by using coupling analysis method in time domain, which determined the preliminary design parameters of mooring system. The sensitivity of the taut system is studied by changing several design parameters such as the top angle of mooring line, cable hole position and method of mooring disposal. In summary, the variation of the motion and dynamic response of the platform and mooring system has been explored and summarized by studying the design process and influential parameter of dynamic characteristics of mooring system and optimizing ideas of relevant parameters, which can further provide technical support and engineering reference for the design and application of the taut mooring system of deepwater Truss Spar platforms.

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