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Collaborating Authors
Results
Committee I.2: Loads
Hermundstad, Ole Andreas (_) | Chai, Shuhong (_) | de Hauteclocque, Guillaume (_) | Dong, Sheng (_) | Fang, Chih-Chung (_) | Johannessen, Thomas B. (_) | Morooka, Celso (_) | Oka, Masayoshi (_) | Prpic-Orลกic, Jasna (_) | Sacchet, Alessandro (_) | Sazidy, Mahmud (_) | Ugurlu, Bahadir (_) | Vettor, Roberto (_) | Wellens, Peter (_)
Committee Mandate Concern for the environmental and operational loads from waves, wind, current, ice, slamming, sloshing, green water, weight distribution and any other operational factors. Consideration shall be given to deterministic and statistical load predictions based on model experiments, full-scale measurements and theoretical methods. Uncertainties in load estimations shall be highlighted. The committee is encouraged to cooperate with the corresponding ITTC committee. Introduction The content of this committee's report is composed in accordance with its mandate by the expertise of its members. Compared to previous reports of the Loads committee the structure is slightly altered, while the topics covered remain basically the same, except that the present report covers ice loads more extensively, while giving less attention to hydroelasticity in waves. There is one section for each of the main types of loads acting on a ship or offshore structure. Hence, Section 2 focuses on wave loads, Section 3 on current and wind loads, while Section 4 concerns ice loads. Next, Section 5 is of a more generic character, concerned with characteristic loads and uncertainty. Finally, Section 6 is devoted to special topics, of which there was only one contribution, namely loads on free-fall lifeboats. Within each of the sections 2 โ 5 there is generally one part focusing on ships and another part focusing on stationary offshore structures. On the lowest level we have distinguished between the different ways of assessing the loads, namely theoretical/numerical methods, laboratory tests and full-scale measurements, although this subdivision is not followed consistently through all sections. In the section on wave loads, a distinction is made between potential theory methods and field methods. The latter group contains numerical methods for solving the Navier-Stokes equations in some form, assessing the flow in the entire fluid field. Potential formulations normally use boundary element methods, although field methods can also be used with potential theory (e.g, Amini-Afshar et al. 2019). The committee has performed a benchmark study on heave/pitch motions and vertical bending moments for a large containership at zero speed in steep regular waves. Existing experimental results have been compared with numerical simulations performed by some of the committee members to investigate the performance of various numerical linear and nonlinear methods, ranging from strip theories to SPH and RANSE solvers. This study is presented in an appendix to the report. To avoid unnecessary overlap with other ISSC committees the focus has been on loads and rigid body responses. Structural dynamic responses, such as springing and whipping of ships, are left to the Dynamic Response Committee, but vortex-induced vibrations of slender structures and ice-induced vibrations are considered in the present report. Loads on offshore wind turbines (OWT) are covered to some extent, although the Offshore Renewable Energy Committee deals with OWT in general.
- North America > United States (1.00)
- Europe (1.00)
- Asia > China (0.67)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
- Overview > Innovation (0.92)
- Transportation > Marine (1.00)
- Energy > Renewable > Wind (1.00)
- Energy > Renewable > Ocean Energy (1.00)
- (4 more...)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5504/12 > Tyra Field (0.99)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5504/11 > Tyra Field (0.99)
- North America > United States > Colorado > Ice Field (0.98)
- Information Technology > Modeling & Simulation (1.00)
- Information Technology > Mathematics of Computing (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (0.67)
- (4 more...)
Design for preventing or minimizing the effects of accidents is termed accidental limit states (ALS) design and is characterized by preventing/minimizing loss of life, environmental damage, and loss of the structure. Collision, grounding, dropped objects, explosion, and fire are traditional accident categories.
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- Geology > Mineral (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Sedimentary Geology > Depositional Environment (0.67)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.67)
- Transportation > Marine (1.00)
- Transportation > Infrastructure & Services (1.00)
- Transportation > Ground (1.00)
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- South America > Brazil > Campos Basin (0.99)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Viosca Knoll > Block 786 > Petronius Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Mississippi Canyon > Block 392 > Appomattox Field (0.99)
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- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Equipment > Offshore drilling units (1.00)
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"In offshore and coastal engineering, metocean refers to the syllabic abbreviation of meteorology and (physical) oceanography" (Wikipedia). Metocean research covers dynamics of the oceaninterface environments: the air-sea surface, atmospheric boundary layer, upper ocean, the sea bed within the wavelength proximity (~100 m for wind-generated waves), and coastal areas. Metocean disciplines broadly comprise maritime engineering, marine meteorology, wave forecast, operational oceanography, oceanic climate, sediment transport, coastal morphology, and specialised technological disciplines for in-situ and remote sensing observations. Metocean applications incorporate offshore, coastal and Arctic engineering; navigation, shipping and naval architecture; marine search and rescue; environmental instrumentation, among others. Often, both for design and operational purposes the ISSC community is interested in Metocean Extremes which include extreme conditions (such as extreme tropical or extra-tropical cyclones), extreme events (such as rogue waves) and extreme environments (such as Marginal Ice Zone, MIZ). Certain Metocean conditions appear extreme, depending on applications (e.g.
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- Summary/Review (1.00)
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- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Sedimentary Geology > Depositional Environment (0.67)
- Geophysics > Electromagnetic Surveying (0.65)
- Geophysics > Seismic Surveying > Seismic Modeling (0.45)
- Transportation > Passenger (1.00)
- Transportation > Marine (1.00)
- Transportation > Infrastructure & Services (1.00)
- (36 more...)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5504/12 > Tyra Field (0.99)
- Europe > Denmark > North Sea > Danish Sector > Central Graben > Block 5504/11 > Tyra Field (0.99)
- North America > United States > Colorado > Ice Field (0.98)
- (18 more...)
- Well Drilling > Well Planning > Trajectory design (1.00)
- Well Drilling > Drillstring Design > Drill pipe selection (1.00)
- Well Drilling > Drilling Operations (1.00)
- (53 more...)
Study on the Resistance Characteristics of a Ship with Moonpool
Lin, Zi-yu (Key Laboratory of High Performane Ship Technology of Ministry of Education, Wuhan University of Technology / Wuhan University of Technology) | Zhou, Li-lan (Key Laboratory of High Performane Ship Technology of Ministry of Education, Wuhan University of Technology / Wuhan University of Technology) | Qin, Jiang-tao (Key Laboratory of High Performane Ship Technology of Ministry of Education, Wuhan University of Technology / Wuhan University of Technology) | Li, Tao (Wuhan Branch of China Classification Society) | Pan, Tian (Wuhan Bureau of Register Shipping and Administration)
ABSTRACT Open moonpool in drillship will cause additional resistance and limit the adaptability of ship. Considering these problems, a numerical method based on STAR-CCM+ was adopted to simulate the resistance of ship with moonpools. Six cases with different step positions and step shapes were calculated to find the effects of moonpools with different steps on ship resistance and hydrodynamic characteristics inside the moonpool. Three gauges were set to monitor the motions of free surface inside the moonpool. Results showed that a significant reduction of ship resistance was found when the ship with a step moonpool comparing with the one with plain moonpool. The change of the shape and position of moonpool step mainly affected the movement amplitude of free surface inside the moonpool, and had little influence on the movement frequency of free surface. INTRODUCTION Moonpools are often used on ships and offshore platforms to facilitate the laying of cables, installation of risers, retracting and discharging equipment and other operations. While, the moonpool is an opening in the hull which is filled with water and own a free surface. Such opening hole may cause strong vibration of the fluid inside the moonpool,which will attack the device inside and cause additional resistance when the ship sailing, and this phenomenon attracted more and more attention. The research approaches of moonpool mainly include model test, theoretical study and numerical simulation. Based on two model tests series that carried out at Delft University of Technology, Riaan van 't Veer et al. (2008) constructed a resistance prediction model for piston type oscillations. The model was verified with a resistance measurement performed at MARIN, showing fair agreement between the predicted and measured resistance. Hammargren et al. (2012) investigated numerically the flow behavior in a moonpool of a drillship and compared the oscillation period of the numerical solution and a value calculated analytically, successfully simulated the flow pattern to get a deeper understanding of the flow phenomena. Sadiq et al. (2008) used CFD commercial software CFX to study two-dimensional and three-dimensional cylindrical and square moonpools under the condition of uniform flow, the results showed that the form of the moonpools had a great influence on the whirlpool shape and the hydrodynamic characteristics of the moonpools. Alsgaard (2010) used CFD method to study the two-dimensional piston motion of the fluid in moonpool, and compared the results with the model test. Heo et al. (2014) concluded that vortex shedding and friction drag act as the main sources of the damping, which depended on the sharpness of the moonpool corners and appendages should be considered for the moonpool dynamics. So it is of great interest to get a deep understanding of how the moonpool affects the resistance of the ship and how it can be improved. Considering these problems, the resistance performance of ship with moonpool was researched through both numerical and experimental methos in this paper. The effects of moonpool geometry on ship resistance in still water were focused. Six cases with different step positions and forms were calculated to find out the relationships among the geometric parameters of the steps, the hydrodynamic response inside the moonpool and the ship resistance.
- Asia > China (0.31)
- Europe > Netherlands > South Holland > Delft (0.24)
- Data Science & Engineering Analytics > Information Management and Systems (0.88)
- Well Drilling > Drilling Equipment > Offshore drilling units (0.55)
A site-specific assessment should be performed before a wind turbine installation vessel (WTIV) operates at a given location. In the present study, structural assessments of a WTIV were performed in the southwest sea of South Korea. Spudcan penetration behavior was calculated, and a load path under the horizontal environmental load was predicted using International Organization for Standardization (ISO) 19905-1. The complex stress and strain state of the soil under the spudcan commonly is simplified, as a boundary condition, to a value of soil stiffness. These boundary conditions include pinned footings, fixed footings, and a foundation model based on the ISO. Soil-structure interaction effects can be considered when the boundary conditions are set as springs with a corresponding yield surface. From the present structural analysis results, a reduction in the stresses of the members at the leg-hull connection could be found. Yield first occurred in the leeward spudcan, after which the moment in the spudcan decreased. Also, penetration depth and soil capacity were found to have had significant impacts on the structural analysis results. Introduction To construct a wind farm at sea, a specialized wind turbine installation vessel (WTIV), as shown in Fig. 1, is needed because of its mobility and cost effectiveness. For the installation of wind turbines, a WTIV should be lifted above the sea surface in order to achieve a steady work environment.
- Europe (0.93)
- Asia > South Korea (0.50)
- Well Drilling > Drilling Equipment > Offshore drilling units (0.68)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (0.67)