Search Results (4)

Floating offshore structures (FOS) must be designed to be stable, to float, and to be able to support other structures for which they were designed. These FOS are needed for different transfer operations in oil terminals. However, water waves affect the motion response of floating buoys. Under normal sea states, the free-floating buoy presents stable periodic responses. However, when moored, they are kept in position. Mooring configurations used to moor buoys in single point mooring (SPM) terminals could require systems such as Catenary Anchor Leg Moorings (CALM) and Single Anchor Leg Moorings (SALM). The CALM buoys are one of the most commonly-utilised type of offshore loading terminal. Due to the wider application of CALM buoy systems, it is necessary to investigate the fluid structure interaction (FSI) and vortex effect on the buoy. In this study, a numerical investigation is presented on a CALM buoy model conducted using Computational Fluid Dynamics (CFD) in ANSYS Fluent version R2 2020. Some hydrodynamic definitions and governing equations were presented to introduce the model. The results presented visualize and evaluate specific motion characteristics of the CALM buoy with emphasis on the vortex effect. The results of the CFD study present a better understanding of the hydrodynamic parameters, reaction characteristics and fluid-structure interaction under random waves. Full article

Due to the demand for oil production in varying water depth regions, the advantage of flexible buoyant conduits has led to an increase in bonded marine hoses for fluid transfer and (un)loading operations. The fluid transfer system for bonded marine hoses is dependent on floating offshore structures (FOS). This paper presents an overview of different systems for sustainable fluid transfer and (un)loading operations via FOS, such as Single Point Mooring (SPM) systems. SPMs are component aspects of the techno-economic design and FOS operation. This review aims to present sustainable fluid transfer technologies while addressing the subject of bonded marine hoses based on application, configuration, test models, hose selection criteria, hose-mooring configurations and operational views. This paper also includes an overview of the hose dynamics, with the loading and unloading (or discharging) techniques for sustainable fluid transfer via marine bonded hoses, based on operational challenges encountered. To dynamically present the hose performance in this review, an overview of the test methods’ guidance as specified in available industry standards was conducted. The pros and cons of marine hose application were also presented. Finally, this study presents different marine hose types and novel design configurations applied in implementing hose-mooring systems. Some concluding remarks with recommended solutions on the technology were presented in this review. Full article

The application of mathematical analysis has been an essential tool applied on Catenary Anchor Leg Mooring (CALM) buoys, Wave Energy Converters (WEC), point absorber buoys, and various single point mooring (SPM) systems. This enables having mathematical models for bonded marine hoses on SPM systems with application with CALM buoys, which are obviously a requisite for the techno-economic design and operation of these floating structures. Hose models (HM) and mooring models (MM) are utilized on a variety of applications such as SPARs, Semisubmersibles, WECs and CALM buoys. CALM buoys are an application of SPM systems. The goal of this review is to address the subject of marine hoses from mathematical modeling and operational views. To correctly reproduce the behavior of bonded marine hoses, including nonlinear dynamics, and to study their performance, accurate mathematical models are required. The paper gives an overview of the statics and dynamics of offshore/marine hoses. The reviews on marine hose behavior are conducted based on theoretical, numerical, and experimental investigations. The review also covers challenges encountered in hose installation, connection, and hang-off operations. State-of-the-art, developments and recent innovations in mooring applications for SURP (subsea umbilicals, risers, and pipelines) are presented. Finally, this study details the relevant materials that are utilized in hoses and mooring implementations. Some conclusions and recommendations are presented based on this review. Full article

A quasi-static analysis and sensitivity investigation of two different mooring configurations—a single anchor leg mooring (SALM) and a three-legged catenary anchor leg system (CALM)—is presented. The analysis aims to indicate what can be expected in terms of requirements for the mooring system size and stiffness. The two mooring systems were designed for the same reference load case, corresponding to a horizontal design load at the wave energy converter (WEC) of 2000 kN and a water depth of 30 m. This reference scenario seems to be representative for large WECs operating in intermediate water depths, such as Weptos, Wave Dragon and many others, including reasonable design safety factors. Around this reference scenario, the main influential parameters were modified in order to investigate their impact on the specifications of the mooring system, e.g. the water depth, the horizontal design load, and a mooring design parameter. Full article