The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
Jianmin Yang - One of the best experts on this subject based on the ideXlab platform.
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An experimental study on the inline wave force on a truncated vertical cylinder
Ships and Offshore Structures, 2020Co-Authors: Hong Xiong, Jianmin Yang, Xinliang TianAbstract:Cylindrical structures are widely used in offshore engineering, such as the Hard Tank of a spar platform, columns of a semi-submersible, jackets, drilling pipes, risers and so on. Interactions between the waves and offshore structures are of great importance for engineering applications. This paper focuses on the inline wave force acting on a truncated vertical circular cylinder. Experimental studies are carried out in the wave Tank at Shanghai Jiao Tong University in China. The diameter of the cylinder (D) is 10 cm and five submergence depths (hs), i.e., hs= 0.5D, 1D, 2D, 3D, 4D, are considered, respectively. The inline force is found to be influenced by the submerged depth of the cylinder, wave steepness and scatter parameter. High-harmonic wave forces and the second-load cycle are also discussed in the paper.
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Experimental Investigation on Added Mass Coefficient of a Truss Spar Subjected to Vortex-Induced Motions
Volume 5: Ocean Engineering; CFD and VIV, 2012Co-Authors: Hui Zhang, Jianmin Yang, Tao Peng, Haining LuAbstract:The prediction of response frequency of Truss Spars is important in the estimation of fatigue damage rates. Response frequency depends on the natural frequency of the structure which is influenced by the added mass.The 1:60 scale Truss Spar model tests have been conducted in towing Tank at Zhejiang Ocean University (ZOU). The Truss Spar model consists of a Hard Tank with removable helical strakes, a truss section and a square soft Tank. Model tests were carried out with simplified mooring system.In this study, results from the experiment subjected to uniform current were reported. The Reynolds numbers varied from 8E04 to 2E05. The mean added mass coefficient and the time-variable added mass coefficient were calculated. The results shown that the predicted natural frequency based on the measured added mass coefficient was approximately equal to the measured mean oscillation frequency. The added mass coefficient calculated from one oscillation cycle to the next varied considerably. The oscillation frequency from one oscillation to the next corresponded to the natural frequency including the added mass coefficient for the same cycle.Copyright © 2012 by ASME
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Strake Design and VIM-Suppression Study of a Cell-Truss Spar
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 6, 2010Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Haining LuAbstract:Along with the development of offshore technology, Spar platforms have been widely used in deep-sea oil and gas exploitation. Due to the deep draft cylinder hull piercing into the water, Spar platforms could be subjected to Vortex-Induced Motions (VIM) in certain current conditions. To mitigate VIM, helical strakes are used on the Spar hulls, and they have been proved to be effective. Cell-Truss Spar is a new concept of Spar platform which has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. It combines some good qualities of the Cell Spar and Truss Spar designs, aiming to bring in the lighter truss section and heave plate damping feature of the Truss Spar to obtain satisfactory heave motion performances, while reduce manufacture and installation difficulties by means of cell concept. Since the Cell-Truss Spar is a new design concept that has physical characteristics which are different from the existing Spars, the global motion performance should be carefully studied and verified. Researches about the VIM performance of the Cell-Truss Spar have been carried out recently (see Wang Ying et al, 2008, etc). Since it is still at the concept design stage, the Cell-Truss Spar configuration is considered without detail strake design in these studies. For the Cell-Truss Spar, which is still on concept design stage at the present time, the design and optimization of the helical strakes is very important to control the VIM response and improve the hydrodynamic performance. In this paper, strake design and VIM-Suppression Study of the Cell-Truss Spar is carried out. As a result of the unique characters on the hull, the outer surface of the Cell-Truss Spar does not form a regular cylinder. Hence, the strakes should be designed more carefully. In this study, four different configurations of strake groups are put forward and studied, and the one with the highest efficiency is chosen to be applied on the Cell-Truss Spar. The fluid field around the Hard Tank of the hull, the vortex disturbance near the strakes, and the forces acting on the Hard Tank with different strakes are simulated by CFD method, and the strake efficiency is assessed through model test combining with CFD computation. The optimized strake configuration is finally chosen, and the VIM performance of the strake-equipped Spar is studied.© 2010 ASME
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Model Test Study on Vortex-Induced Motions of a Floating Cylinder
Volume 5: Polar and Arctic Sciences and Technology; CFD and VIV, 2009Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Xin LiAbstract:Vortex-Induced Motions (VIM) under current flow is an important issue for surface piercing cylinders, such as Spar platforms and floating buoys, since it affects the motion performance of these structures greatly. In recent years this phenomenon attracts much attention and many researchers have been making efforts to deal with this problem. VIM is such a complicated phenomenon that more fundamental studies are needed to understand the essence behind VIM. This paper mainly concentrates on a circular cylinder, aiming to eliminate outside influences and reveal the inherent characteristic of vortex-induced motion mechanism. A circular cylinder with an aspect ratio of 1:2.4, which could be considered as a scale model for the Hard Tank of a typical Truss Spar, is studied by experimental method to investigate the surrounding fluid field, the excitation forces and Vortex-Induced Motion characteristics under various governing parameters, such as the current velocity and direction, the mooring stiffness and distribution, the use and efficiency of helical strakes, and so on. By using a simple flow visualization system, the unsteady flow passing the circular cylinder and the vortices in the wake are captured and recorded. The cylinder is tested respectively under fixed, forced-motion and elastically moored conditions. The fluid field, the vortex structures, and the lift and drag forces under fixed and forced-motion conditions are measured, the VIM performance of the cylinder with two different mooring distributions are studied, and strake efficiency is studied considering current directionality and strake height influence.Copyright © 2009 by ASME
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CFD Analysis of Unsteady Flows Around a New Cell-Truss Spar and the Corresponding Vortex-Induced Motions
Volume 5: Materials Technology; CFD and VIV, 2008Co-Authors: Ying Wang, Jianmin Yang, Xin LiAbstract:A new configuration of Spar platform called the Cell-Truss Spar has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. Since the Cell-Truss Spar is a new design concept that has several physical characteristics which are different from those of the present Classic, Truss and Cell Spars, many aspects of its performances in various sea conditions should be carefully studied. For any type of Spars, Vortex-Induced Motions (VIM) under current flow is an important consideration since it not only affects the motion performance of the Spar, but also reacts on the fatigue analysis and Spar mooring design. This paper mainly discusses the unsteady flows around the new Cell-Truss Spar and the corresponding vortex-induced motion performances of the Spar in uniform currents. A CFD model of the Cell-Truss Spar upper hull (without strake designs for VIM mitigation since it’s still at the concept design stage at the present time) with a scale ratio of 1:100 is created and numerical simulations at different current conditions are performed. The software FLUENT is chosen as the computational fluid dynamic tool to simulate the flow fields around the Cell-Truss Spar and the resulting vortex-induced motions. Both 2D and 3D simulations are carried out. Dynamic meshes and user defined functions are used in the fluid-structure interaction for solving the equations of motion. The SST k-ω method is used as the turbulence model in the 2D simulation and the Detached Eddy Simulation (DES) is used in the 3D simulation. In the 2D simulation, the unsteady flows around the Cell-Truss Spar Hard Tank at different Reynolds numbers are calculated and the corresponding vortex shedding features and other fluid parameters are obtained and analyzed. Moreover, in order to set up a baseline for the comparison and analysis of the Cell-Truss Spar, a typical Truss Spar Hard Tank with the same diameter and draft is also modeled and calculated. Comparisons with several classical experimental and numerical results are conducted to validate the numerical method. The Cell-Truss Spar hull VIM responses are then simulated. For the 3D simulation, the fluid domain is made of a hybrid mesh comprising of millions of wedgy and hexahedral elements. Since 3D simulation is very time-consuming, only the results of the nonlinear flow field features for the currents passing the stationary Spar are presented in this paper, and more advanced studies related to this subject including both numerical and experimental investigations would be carried out successively.© 2008 ASME
Ying Wang - One of the best experts on this subject based on the ideXlab platform.
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Strake Design and VIM-Suppression Study of a Cell-Truss Spar
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 6, 2010Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Haining LuAbstract:Along with the development of offshore technology, Spar platforms have been widely used in deep-sea oil and gas exploitation. Due to the deep draft cylinder hull piercing into the water, Spar platforms could be subjected to Vortex-Induced Motions (VIM) in certain current conditions. To mitigate VIM, helical strakes are used on the Spar hulls, and they have been proved to be effective. Cell-Truss Spar is a new concept of Spar platform which has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. It combines some good qualities of the Cell Spar and Truss Spar designs, aiming to bring in the lighter truss section and heave plate damping feature of the Truss Spar to obtain satisfactory heave motion performances, while reduce manufacture and installation difficulties by means of cell concept. Since the Cell-Truss Spar is a new design concept that has physical characteristics which are different from the existing Spars, the global motion performance should be carefully studied and verified. Researches about the VIM performance of the Cell-Truss Spar have been carried out recently (see Wang Ying et al, 2008, etc). Since it is still at the concept design stage, the Cell-Truss Spar configuration is considered without detail strake design in these studies. For the Cell-Truss Spar, which is still on concept design stage at the present time, the design and optimization of the helical strakes is very important to control the VIM response and improve the hydrodynamic performance. In this paper, strake design and VIM-Suppression Study of the Cell-Truss Spar is carried out. As a result of the unique characters on the hull, the outer surface of the Cell-Truss Spar does not form a regular cylinder. Hence, the strakes should be designed more carefully. In this study, four different configurations of strake groups are put forward and studied, and the one with the highest efficiency is chosen to be applied on the Cell-Truss Spar. The fluid field around the Hard Tank of the hull, the vortex disturbance near the strakes, and the forces acting on the Hard Tank with different strakes are simulated by CFD method, and the strake efficiency is assessed through model test combining with CFD computation. The optimized strake configuration is finally chosen, and the VIM performance of the strake-equipped Spar is studied.© 2010 ASME
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Model Test Study on Vortex-Induced Motions of a Floating Cylinder
Volume 5: Polar and Arctic Sciences and Technology; CFD and VIV, 2009Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Xin LiAbstract:Vortex-Induced Motions (VIM) under current flow is an important issue for surface piercing cylinders, such as Spar platforms and floating buoys, since it affects the motion performance of these structures greatly. In recent years this phenomenon attracts much attention and many researchers have been making efforts to deal with this problem. VIM is such a complicated phenomenon that more fundamental studies are needed to understand the essence behind VIM. This paper mainly concentrates on a circular cylinder, aiming to eliminate outside influences and reveal the inherent characteristic of vortex-induced motion mechanism. A circular cylinder with an aspect ratio of 1:2.4, which could be considered as a scale model for the Hard Tank of a typical Truss Spar, is studied by experimental method to investigate the surrounding fluid field, the excitation forces and Vortex-Induced Motion characteristics under various governing parameters, such as the current velocity and direction, the mooring stiffness and distribution, the use and efficiency of helical strakes, and so on. By using a simple flow visualization system, the unsteady flow passing the circular cylinder and the vortices in the wake are captured and recorded. The cylinder is tested respectively under fixed, forced-motion and elastically moored conditions. The fluid field, the vortex structures, and the lift and drag forces under fixed and forced-motion conditions are measured, the VIM performance of the cylinder with two different mooring distributions are studied, and strake efficiency is studied considering current directionality and strake height influence.Copyright © 2009 by ASME
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CFD Analysis of Unsteady Flows Around a New Cell-Truss Spar and the Corresponding Vortex-Induced Motions
Volume 5: Materials Technology; CFD and VIV, 2008Co-Authors: Ying Wang, Jianmin Yang, Xin LiAbstract:A new configuration of Spar platform called the Cell-Truss Spar has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. Since the Cell-Truss Spar is a new design concept that has several physical characteristics which are different from those of the present Classic, Truss and Cell Spars, many aspects of its performances in various sea conditions should be carefully studied. For any type of Spars, Vortex-Induced Motions (VIM) under current flow is an important consideration since it not only affects the motion performance of the Spar, but also reacts on the fatigue analysis and Spar mooring design. This paper mainly discusses the unsteady flows around the new Cell-Truss Spar and the corresponding vortex-induced motion performances of the Spar in uniform currents. A CFD model of the Cell-Truss Spar upper hull (without strake designs for VIM mitigation since it’s still at the concept design stage at the present time) with a scale ratio of 1:100 is created and numerical simulations at different current conditions are performed. The software FLUENT is chosen as the computational fluid dynamic tool to simulate the flow fields around the Cell-Truss Spar and the resulting vortex-induced motions. Both 2D and 3D simulations are carried out. Dynamic meshes and user defined functions are used in the fluid-structure interaction for solving the equations of motion. The SST k-ω method is used as the turbulence model in the 2D simulation and the Detached Eddy Simulation (DES) is used in the 3D simulation. In the 2D simulation, the unsteady flows around the Cell-Truss Spar Hard Tank at different Reynolds numbers are calculated and the corresponding vortex shedding features and other fluid parameters are obtained and analyzed. Moreover, in order to set up a baseline for the comparison and analysis of the Cell-Truss Spar, a typical Truss Spar Hard Tank with the same diameter and draft is also modeled and calculated. Comparisons with several classical experimental and numerical results are conducted to validate the numerical method. The Cell-Truss Spar hull VIM responses are then simulated. For the 3D simulation, the fluid domain is made of a hybrid mesh comprising of millions of wedgy and hexahedral elements. Since 3D simulation is very time-consuming, only the results of the nonlinear flow field features for the currents passing the stationary Spar are presented in this paper, and more advanced studies related to this subject including both numerical and experimental investigations would be carried out successively.© 2008 ASME
Xin Li - One of the best experts on this subject based on the ideXlab platform.
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Model Test Study on Vortex-Induced Motions of a Floating Cylinder
Volume 5: Polar and Arctic Sciences and Technology; CFD and VIV, 2009Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Xin LiAbstract:Vortex-Induced Motions (VIM) under current flow is an important issue for surface piercing cylinders, such as Spar platforms and floating buoys, since it affects the motion performance of these structures greatly. In recent years this phenomenon attracts much attention and many researchers have been making efforts to deal with this problem. VIM is such a complicated phenomenon that more fundamental studies are needed to understand the essence behind VIM. This paper mainly concentrates on a circular cylinder, aiming to eliminate outside influences and reveal the inherent characteristic of vortex-induced motion mechanism. A circular cylinder with an aspect ratio of 1:2.4, which could be considered as a scale model for the Hard Tank of a typical Truss Spar, is studied by experimental method to investigate the surrounding fluid field, the excitation forces and Vortex-Induced Motion characteristics under various governing parameters, such as the current velocity and direction, the mooring stiffness and distribution, the use and efficiency of helical strakes, and so on. By using a simple flow visualization system, the unsteady flow passing the circular cylinder and the vortices in the wake are captured and recorded. The cylinder is tested respectively under fixed, forced-motion and elastically moored conditions. The fluid field, the vortex structures, and the lift and drag forces under fixed and forced-motion conditions are measured, the VIM performance of the cylinder with two different mooring distributions are studied, and strake efficiency is studied considering current directionality and strake height influence.Copyright © 2009 by ASME
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CFD Analysis of Unsteady Flows Around a New Cell-Truss Spar and the Corresponding Vortex-Induced Motions
Volume 5: Materials Technology; CFD and VIV, 2008Co-Authors: Ying Wang, Jianmin Yang, Xin LiAbstract:A new configuration of Spar platform called the Cell-Truss Spar has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. Since the Cell-Truss Spar is a new design concept that has several physical characteristics which are different from those of the present Classic, Truss and Cell Spars, many aspects of its performances in various sea conditions should be carefully studied. For any type of Spars, Vortex-Induced Motions (VIM) under current flow is an important consideration since it not only affects the motion performance of the Spar, but also reacts on the fatigue analysis and Spar mooring design. This paper mainly discusses the unsteady flows around the new Cell-Truss Spar and the corresponding vortex-induced motion performances of the Spar in uniform currents. A CFD model of the Cell-Truss Spar upper hull (without strake designs for VIM mitigation since it’s still at the concept design stage at the present time) with a scale ratio of 1:100 is created and numerical simulations at different current conditions are performed. The software FLUENT is chosen as the computational fluid dynamic tool to simulate the flow fields around the Cell-Truss Spar and the resulting vortex-induced motions. Both 2D and 3D simulations are carried out. Dynamic meshes and user defined functions are used in the fluid-structure interaction for solving the equations of motion. The SST k-ω method is used as the turbulence model in the 2D simulation and the Detached Eddy Simulation (DES) is used in the 3D simulation. In the 2D simulation, the unsteady flows around the Cell-Truss Spar Hard Tank at different Reynolds numbers are calculated and the corresponding vortex shedding features and other fluid parameters are obtained and analyzed. Moreover, in order to set up a baseline for the comparison and analysis of the Cell-Truss Spar, a typical Truss Spar Hard Tank with the same diameter and draft is also modeled and calculated. Comparisons with several classical experimental and numerical results are conducted to validate the numerical method. The Cell-Truss Spar hull VIM responses are then simulated. For the 3D simulation, the fluid domain is made of a hybrid mesh comprising of millions of wedgy and hexahedral elements. Since 3D simulation is very time-consuming, only the results of the nonlinear flow field features for the currents passing the stationary Spar are presented in this paper, and more advanced studies related to this subject including both numerical and experimental investigations would be carried out successively.© 2008 ASME
Haining Lu - One of the best experts on this subject based on the ideXlab platform.
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Experimental Investigation on Added Mass Coefficient of a Truss Spar Subjected to Vortex-Induced Motions
Volume 5: Ocean Engineering; CFD and VIV, 2012Co-Authors: Hui Zhang, Jianmin Yang, Tao Peng, Haining LuAbstract:The prediction of response frequency of Truss Spars is important in the estimation of fatigue damage rates. Response frequency depends on the natural frequency of the structure which is influenced by the added mass.The 1:60 scale Truss Spar model tests have been conducted in towing Tank at Zhejiang Ocean University (ZOU). The Truss Spar model consists of a Hard Tank with removable helical strakes, a truss section and a square soft Tank. Model tests were carried out with simplified mooring system.In this study, results from the experiment subjected to uniform current were reported. The Reynolds numbers varied from 8E04 to 2E05. The mean added mass coefficient and the time-variable added mass coefficient were calculated. The results shown that the predicted natural frequency based on the measured added mass coefficient was approximately equal to the measured mean oscillation frequency. The added mass coefficient calculated from one oscillation cycle to the next varied considerably. The oscillation frequency from one oscillation to the next corresponded to the natural frequency including the added mass coefficient for the same cycle.Copyright © 2012 by ASME
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Strake Design and VIM-Suppression Study of a Cell-Truss Spar
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 6, 2010Co-Authors: Ying Wang, Jianmin Yang, Tao Peng, Haining LuAbstract:Along with the development of offshore technology, Spar platforms have been widely used in deep-sea oil and gas exploitation. Due to the deep draft cylinder hull piercing into the water, Spar platforms could be subjected to Vortex-Induced Motions (VIM) in certain current conditions. To mitigate VIM, helical strakes are used on the Spar hulls, and they have been proved to be effective. Cell-Truss Spar is a new concept of Spar platform which has recently been put forward by State Key Laboratory of Ocean Engineering (SKLOE) of Shanghai Jiao Tong University. It combines some good qualities of the Cell Spar and Truss Spar designs, aiming to bring in the lighter truss section and heave plate damping feature of the Truss Spar to obtain satisfactory heave motion performances, while reduce manufacture and installation difficulties by means of cell concept. Since the Cell-Truss Spar is a new design concept that has physical characteristics which are different from the existing Spars, the global motion performance should be carefully studied and verified. Researches about the VIM performance of the Cell-Truss Spar have been carried out recently (see Wang Ying et al, 2008, etc). Since it is still at the concept design stage, the Cell-Truss Spar configuration is considered without detail strake design in these studies. For the Cell-Truss Spar, which is still on concept design stage at the present time, the design and optimization of the helical strakes is very important to control the VIM response and improve the hydrodynamic performance. In this paper, strake design and VIM-Suppression Study of the Cell-Truss Spar is carried out. As a result of the unique characters on the hull, the outer surface of the Cell-Truss Spar does not form a regular cylinder. Hence, the strakes should be designed more carefully. In this study, four different configurations of strake groups are put forward and studied, and the one with the highest efficiency is chosen to be applied on the Cell-Truss Spar. The fluid field around the Hard Tank of the hull, the vortex disturbance near the strakes, and the forces acting on the Hard Tank with different strakes are simulated by CFD method, and the strake efficiency is assessed through model test combining with CFD computation. The optimized strake configuration is finally chosen, and the VIM performance of the strake-equipped Spar is studied.© 2010 ASME
John Murray - One of the best experts on this subject based on the ideXlab platform.
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Comparison Between Numerical Prediction and Model Tests Measurements on the Centerwell Tank of a Radial Wellbay Spar
Volume 1: Offshore Technology, 2012Co-Authors: Edmund Muehlner, John Murray, Surya Banumurthy, Chandan LakhotiaAbstract:The radial wellbay (RAW) Spar is, for the most part, based on conventional Truss Spar technology. The primary difference between the RAW Spar and the conventional Truss Spar is the wellbay arrangement.An integral structural component of the RAW Spar is the ABCD (Adjustable Buoyancy Centerwell Device) located in the lower portion of the centerwell. The ABCD is connected to the interior of the Hard Tank using a number of shear plates. The ABCD captures the buoyancy in the open centerwell and contributes to the total buoyancy of the Hard Tank. As an option, the ABCD can be used for in-hull storage. On the RAW drilling Spar, the ABCD can be used to support the setback and pipe racking system.Design applications using the ABCD raise an additional requirement in the design of the Hard Tank, specifically, an accurate estimate of the load in the structure that connects the ABCD to the Hard Tank. Contributions to this load come from the inertia effect of the Spar motions, hydrostatic responses affected by ballast conditions in the device, and hydrodynamic forces affected by pressure in the riser slot gap. Connection loads are required to design the structure connecting the ABCD to the interior walls of the Hard Tank.An ABAQUS™ based time domain semi-empirical model was developed to predict the local and global loads on the ABCD. A series of 1:50 scale model tests on the RAW Spar were carried out at the OTRC basin in College Station, Texas. The model’s ABCD, mounted on a dynamometer system inside the Hard Tank, was used to measure the six-degree-of-freedom forces between the Hard Tank and the ABCD. The paper focuses on a comparison of the predicted and measured loads.Copyright © 2012 by ASME
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Model Tests on a Radial Wellbay Spar in Gulf of Mexico, Norwegian Sea and Offshore Brazil Environments
Volume 1: Offshore Technology, 2012Co-Authors: John Murray, Edmund Muehlner, Surya Banumurthy, Guibog ChoiAbstract:A model test campaign on a 1:50 scale model of a Radial Wellbay Spar (RAW) Spar was carried out at the OTRC facility in College Station, Texas. The campaign subjected the model to wind, wave, and current environments from the Central Gulf of Mexico, the Norwegian Sea, and offshore Brazil. Time traces of dynamic wind loads were predetermined from computations using drag coefficients and estimated wind load areas of the topsides. A servo controlled line mechanism was used to apply the wind load to the model topsides. Current forces were modeled using static weights connected at the appropriate elevation on the model. Ten (10) top-tensioned risers (TTRs) were modeled in terms of stiffness and top tension using four equivalent model TTRs. Horizontal restoring forces of the prototype mooring were modeled using a four-model line arrangement. The model was instrumented to measure six-degree-of-freedom rigid body motions, air gap around the deck, wave run-up, water elevation in the riser gap in the Hard Tank, and mooring and TTR tensions. Global loads on an internal structural component between the centerwell device and Hard Tank were measured in all environments. Data comparisons were based on selected time traces of various responses and Weibull distributions to predict extreme values. In general, good agreement was found between the measured and predicted values.Copyright © 2012 by ASME
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Improved Efficiencies in Truss Spar Designs Without Dry Transportation Constraints
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 1, 2010Co-Authors: John Murray, Guibog ChoiAbstract:Truss Spars that are designed to accommodate dry transportation encounter certain constraints because the overall length and Hard Tank diameter of the Spar cannot exceed the limits of the transport vessel. When these constraints are removed, hulls can be longer. Increased length allows the fixed ballast and Hard Tank steel weights to be reduced. Although the truss steel weight is increased for deeper drafts, there is an overall savings in steel when the Hard Tank and soft Tank are taken into account. The heave response of a Spar can be adversely affected by tensioners used to support TTRs. Deeper drafts can improve heave response and an additional heave plate can be introduced if necessary.
