Academic literature on the topic 'Underwater pipelines Hydrodynamics'
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Journal articles on the topic "Underwater pipelines Hydrodynamics"
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PENG, XUE-LIN, and HONG HAO. "A NUMERICAL STUDY OF DAMAGE DETECTION OF UNDERWATER PIPELINE USING VIBRATION-BASED METHOD." International Journal of Structural Stability and Dynamics 12, no. 03 (May 2012): 1250021. http://dx.doi.org/10.1142/s0219455412500216.
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This paper presents a numerical investigation of the feasibility of condition monitoring of untrenched pipelines at seabed through ambient vibration measurements. A finite element (FE) model is developed to calculate the dynamic responses of pipelines to ambient wave forces. The model takes into consideration the interaction between the ocean waves, submarine pipeline, and seabed. The fluid around the pipeline is simulated using the acoustic fluid elements, while soil is simulated by springs and dashpots. The ambient hydrodynamic force in the marine environment is simulated based on the Joint North Sea Wave Observation Project (JONSWAP) spectrum. The transfer function from the wave surface elevation to the wave force is used to get the wave force spectrum. The dynamic responses of the pipe structure with different assumed damage conditions to the ambient wave forces are calculated. The calculated dynamic responses are assumed as measured ambient vibration data in condition monitoring to extract the pipeline vibration properties, which in turn are used in the FE model updating calculation to identify the pipeline conditions. Different noise levels are introduced into the calculated dynamic responses to simulate uncertainties that may arise from measurement and ambient hydrodynamic environment. The effect of noise levels on the extraction of pipeline vibration properties, and on the identification of the pipeline conditions is investigated.
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Kornilova, Z. G., G. S. Ammosov, and D. S. Ivanov. "Concerning the Stream Turbidity During the Laying of the Underwater Crossing of the Main Pipeline Across the River Lena." IOP Conference Series: Earth and Environmental Science 988, no. 3 (February 1, 2022): 032036. http://dx.doi.org/10.1088/1755-1315/988/3/032036.
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Abstract The stream turbidity significantly changes during the river bed evolution. It depends on the sediment storage, which is affected by the bottom dredging works, the construction of underwater crossings of main pipelines, bridge crossings, and others. In the present paper, we consider the change in the stream turbidity during the laying of the underwater crossings of the main pipelines (ML) across the river Lena. A significant increase in the water turbidity and the discharge of suspended sediment has been detected during the construction of linear structures intended for transporting the energy resources. The river bed erosion in the trench area is one of the factors of the decrease in the service life of the underwater crossing of ML when the siphon is trench laid across a water channel. When the bottom is scoured, and the siphon of the underwater pipeline is denuded, significant hydrodynamic loads not specified by the project are added to the operational loads. Torsional, bending, and overturning moments, as well as the phenomena of hydro-abrasive erosive wear, develop [1]. They lead to fatigue failure of individual sections of the underwater pipeline on the base metal and welded joints. It is crucial to conduct further studies to assess the deterioration degree of the ecological state of the river Lena.
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Hosseini, Mohammad Khalaj Amir, Omid Omidi, Ali Meghdari, and Gholamreza Vossoughi. "A Composite Rigid Body Algorithm for Modeling and Simulation of an Underwater Vehicle Equipped With Manipulator Arms." Journal of Offshore Mechanics and Arctic Engineering 128, no. 2 (August 23, 2005): 119–32. http://dx.doi.org/10.1115/1.2185682.
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In this paper, modeling and simulation of an underwater vehicle equipped with manipulator arms, using a composite rigid body algorithm, will be discussed. Because of the increasing need for unmanned underwater vehicles (UUVs) in oil and gas projects in the Persian Gulf, for doing operations such as inspection of offshore jackets, subsea pipelines, and submarine cables, and also pre-installation survey and post-laid survey of submarine pipelines and cables, design and construction of “SROV” was developed in Sharif University of Technology, and at the design stage behavior of the underwater vehicles was studied. In this paper, an efficient dynamic simulation algorithm is developed for an UUV equipped with m manipulators so that each of them has N degrees of freedom. In addition to the effects of the mobile base, the various hydrodynamic forces exerted on these systems in an underwater environment are also incorporated into the simulation. The effects modeled in this work are added mass, viscous drag, fluid acceleration, and buoyancy forces. For drag forces, the emphasis here is on the modeling of the pressure drag. Recent advances in underwater position and velocity sensing enable real-time centimeter-precision position measurements of underwater vehicles. With these advances in position sensing, our ability to precisely control the hovering and low-speed trajectory of an underwater vehicle is limited principally by our understanding of the vehicle’s dynamics and the dynamics of the bladed thrusters commonly used to actuate dynamically positioned marine vehicles. So the dynamics of thrusters are developed and an appropriate mapping matrix dependent on the position and orientation of the thrusters on the vehicle is used to calculate resultant forces and moments of the thrusters on the center of gravity of the vehicle. It should be noted that hull-propeller and propeller-propeller interactions are considered in the modeling too. Finally, the results of the simulations, for an underwater vehicle equipped with 1 two degrees of freedom manipulator, are presented and discussed in detail.
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Korchagin, N. N., and I. Yu Vladimirov. "On the effect of circulatory flow around objects in marine medium and atmosphere." Доклады Академии наук 488, no. 2 (September 24, 2019): 207–11. http://dx.doi.org/10.31857/s0869-56524882207-211.
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Analytical expressions of the hydrodynamic reaction of a point dipole in two-layer circulatory fluid flow around it are obtained. The dependence of the wave resistance and the lift force on the flow velocity, the density jump, the circulation and the depth of the sea is investigated. It is shown that the influence of the velocity circulation leads to a change in the lift force acting on the dipole. Moreover, such changes are reversible in a relatively narrow range of the velocity of flow around the pipeline. Along with the pipeline, such features in the nature of the effect of circulation on the lift force can be manifested for self-propelled underwater objects and aerial vehicles.
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Xing, Yihan, Marek Jan Janocha, Guang Yin, and Muk Chen Ong. "CFD Investigation on Hydrodynamic Resistance of a Novel Subsea Shuttle Tanker." Journal of Marine Science and Engineering 9, no. 12 (December 10, 2021): 1411. http://dx.doi.org/10.3390/jmse9121411.
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The Subsea Shuttle Tanker (SST) was proposed by Equinor as an alternative to subsea pipelines and surface tankers for the transportation of liquid carbon dioxide (CO2) from existing offshore/land facilities to marginal subsea fields. In contrast to highly weather-dependent surface tanker operations, the SST can operate in any condition underwater. Low resistance is paramount to achieving maximum range. In this paper, the resistance of the SST at an operating forward speed of 6 knots (3.09 m/s) and subject to an incoming current velocity of 1 m/s is computed using Computational Fluid Dynamics (CFD). The Delayed Detached Eddy Simulation (DDES) method is used. This method combines features of Reynolds-Averaged Navier–Stokes Simulation (RANS) in the attached boundary layer parts at the near-wall regions, and Large Eddy Simulation (LES) at the unsteady, separated regions near to the propeller. The force required to overcome forward resistance is calculated to be 222 kN and agrees well with experimental measurements available in the open literature. The corresponding power consumption is calculated to be 927 kW, highlighting the high efficiency of the SST. The method presented in this paper is general and can be used for resistance optimization studies of any underwater vessel.
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Gilyov, E. E., S. N. Shubin, A. I. Borovkov, and A. K. Abramian. "Modeling of hydrodynamic impact on underwater gas pipeline in A trench with liquefied soil." Computational Continuum Mechanics 4, no. 3 (2011): 41–47. http://dx.doi.org/10.7242/1999-6691/2011.4.3.25.
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Liu, Xiaodong, Yuli Hu, Zhaoyong Mao, and Wenlong Tian. "Numerical Simulation of the Hydrodynamic Performance and Self-Propulsion of a UUV near the Seabed." Applied Sciences 12, no. 14 (July 9, 2022): 6975. http://dx.doi.org/10.3390/app12146975.
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Unmanned underwater vehicles (UUV) face maneuverability and rapidity challenges when they are applied for detecting and repairing submarine oil and gas pipelines, and fiber cables near the seabed. This research establishes numerical models of the bare UUV and self-propelled UUV near the seabed using the computational fluid dynamics (CFD) method. The effect of dimensionless distance Hd and ReL on the hydrodynamic performance of the vehicle and the interaction between the hull and the propeller is investigated. The range of Hd is 1.5D–10D, and the ReL is 9.97 × 105~7.98 × 106. Findings indicate that: (1) There is an obvious strong coupling between the hydrodynamic performance of the bare UUV and Hd. With the increase of Hd, the hydrodynamic performance such as Cd, the absolute value of Cl and my decreases continuously and finally tends to be stable. The absolute values of Cd and Cl increase with the increase of ReL. The change trend of my is opposite to that of Cl. (2) The variation trend of hydrodynamic performance of the self-propelled UUV with Hd is consistent with those of the bare UUV. Additionally, it increases to some extent, respectively, compared with the bare UUV. (3) The self-propelled characteristics such as t, ηH, w and ηi are weakly related to Hd. The t and ηi increase with the increasing of ReL, while ηH and w decrease with the increasing of ReL.
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Fernandes, Matheus C., Mehdi Saadat, Patrick Cauchy-Dubois, Chikara Inamura, Ted Sirota, Garrett Milliron, Hossein Haj-Hariri, Katia Bertoldi, and James C. Weaver. "Mechanical and hydrodynamic analyses of helical strake-like ridges in a glass sponge." Journal of The Royal Society Interface 18, no. 182 (September 2021): 20210559. http://dx.doi.org/10.1098/rsif.2021.0559.
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From the discovery of functionally graded laminated composites, to near-structurally optimized diagonally reinforced square lattice structures, the skeletal system of the predominantly deep-sea sponge Euplectella aspergillum has continued to inspire biologists, materials scientists and mechanical engineers. Building on these previous efforts, in the present study, we develop an integrated finite element and fluid dynamics approach for investigating structure–function relationships in the complex maze-like organization of helical ridges that surround the main skeletal tube of this species. From these investigations, we discover that not only do these ridges provide additional mechanical reinforcement, but perhaps more significantly, provide a critical hydrodynamic benefit by effectively suppressing von Kármán vortex shedding and reducing lift forcing fluctuations over a wide range of biologically relevant flow regimes. By comparing the disordered sponge ridge geometry to other more symmetrical strake-based vortex suppression systems commonly employed in infrastructure applications ranging from antennas to underwater gas and oil pipelines, we find that the unique maze-like ridge organization of E. aspergillum can completely suppress vortex shedding rather than delaying their shedding to a more downstream location, thus highlighting their potential benefit in these engineering contexts.
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Ji, Shunying, Xiaodong Chen, and Lu Liu. "Coupled DEM-SPH Method for Interaction between Dilated Polyhedral Particles and Fluid." Mathematical Problems in Engineering 2019 (August 21, 2019): 1–11. http://dx.doi.org/10.1155/2019/4987801.
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The discrete element method (DEM) and smoothed particle hydrodynamics (SPH) can be adopted to simulate the granular materials and fluid media respectively. The DEM-SPH coupling algorithm can be developed for the dynamic interaction between the two media. When the particle material is simulated by polyhedral element, a fluid-solid coupling interface would lead to the complex geometry between the granular particle and the fluid. The boundary particle method is traditionally used for the fluid-solid interface but with low computational efficiency. In this paper, the dilated polyhedral element is constructed based on Minkowski sum theory, while the contact force between the elements is calculated by Hertzian contact model. Accordingly the dilated polyhedra based DEM is established. The weakly compressible SPH is adopted to simulate the fluid medium, while the interaction on the geometrically complex fluid-solid interface is evaluated with the repulsive force model which can be determined by the contact detection between SPH particles and solid particles in geometry. This method avoids the storage and calculation of a large number of boundary particles, which can be potentially applied for the complex fluid-solid boundary. In order to improve the computational efficiency, a GPU-based parallel algorithm is employed to achieve high performance computation of SPH. The acceleration of the parallel algorithm is evaluated by the cases of dam break. The numerical simulation of the impact of dam break on cubes is implemented. The simulation results are verified with the corresponding experimental and simulation results. Therefore, the rationality and accuracy of the DEM-SPH coupling method for numerical simulation of the interaction between granular materials and fluid media are illustrated. This method is then adopted for the impact of falling rocks on underwater pipeline. The force of water and rocks on the pipeline is analyzed. This method can be further applied for real engineering problems.
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Ondara, Koko, Ulung Jantama Wisha, and Serli Marlinda Panjaitan. "Particle Tracking Model Approach for Analyzing Crude Oil Spill (Palm Fatty Acid Distillate) in Bayur Bay Based on Navier Stokes Discrete." Buletin Oseanografi Marina 10, no. 1 (January 7, 2021): 67–74. http://dx.doi.org/10.14710/buloma.v10i1.29036.
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Oil spilled in the marine ecosystem may be induced by some sources which alter over time and location. Oil leakage from offshore oil drilling, underwater oil pipeline leakage, etc., are the possible source of oil spill pollution. Marine pollution generated by oil spilling occurred in Padang City in 2017. Palm Fatty Acid Distillate (PFAD) spilled within Bayur Bay Harbor due to a leaking storage tank. As much as 50 tons of PFAD overflowed and commenced to pollute Bayur coastal bay. This study aimed to determine the distribution pattern of oil spills throughout the Bayur Bay based on a hydrodynamical model. We employed some oceanographic data and PFAD characteristics obtained directly from survey results. We simulated the particle tracking model for 30 days since the PFAD spilled within the port. The model developed applied the Least Square method to analyze tidal data and a flexible mesh as a model basis, while the governing equation used is Navier Stoke discrete. During a month of simulation, the dominant particles' distribution is still spinning around the Bayur Bay due to the weak current characteristics with the magnitude ranging from 0.02-0.06 m/s. The lighter PFAD particle mass tended to move faster throughout the bay and settled in the coastal area. It will pollute the coastal system even though it is going to be decomposed chemically in the sediment.
Dissertations / Theses on the topic "Underwater pipelines Hydrodynamics"
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Yeow, Kervin. "Three dimensional scour along offshore pipelines." University of Western Australia. School of Civil and Resource Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0008.
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Three-dimensional scour propagation along offshore pipelines is a major reason to pipeline failures in an offshore environment. Although the research on scour in both numerical and experimental aspect has been extensive over the last three decades, the focus of the investigation has been limited to the two-dimensional aspect. The knowledge on three-dimensional scour is still limited. This dissertation presents the results of an experimental investigation on threedimensional scour along offshore pipelines in (1) steady currents (2) waves only and (3) combined waves and current. The major emphasis of the investigation is to investigate the propagation of the scour hole along the pipeline after the initiation of scour. Physical experiments conducted were used to quantify the effects of various parameters on scour propagation velocities along the pipeline. The problem of monitoring real time scour below a pipeline was solved by using specifically developed conductivity scour probes. Effects of various parameters such as pipeline embedment depth, incoming flow Shields parameter, Keuglegan- Carpenter (KC) number and flow incident angle to the pipeline on scour propagation velocities along the pipeline were investigated. The investigations clearly reveal that scour propagation velocities generally increase with the increase of flow but decrease with the increase of the pipeline embedment depth. A general predictive formula for scour propagation velocities is proposed and validated against the experimental results. There are still some common issues related to pipeline scour that is lacking in the literature to date. One of these issues is the effects of Reynolds number on two-dimensional scour beneath pipelines. A numerical approach was adopted to investigate the Reynolds-number dependence of two-dimensional scour beneath offshore pipelines in steady currents. A novel wall function is proposed in calculating the suspended sediment transport rate in the model. The effects of Reynolds number were investigated by simulating the same undisturbed Shields parameters in both model and prototype but with different values of Reynolds number in two separate calculations. The results revealed that scour depths for prototype pipelines are about 10~15% smaller than those for model pipelines. The normalized time scales was found to be approximately the same, and the simulated scour profiles for the model pipelines agree well with the experimental results from an independent study. The backfilling of pipeline trenches is also an important issue to the design and management of offshore pipelines. A numerical model is developed to simulate the self-burial of a pipeline trench. Morphological evolutions of a pipeline trench under steady-current or oscillatory-flow conditions are simulated with/without a pipeline inside the trench. The two-dimensional Reynolds-averaged continuity and Navier-Stokes equations with the standard k-e turbulence closure, as well as the sediment transport equations, are solved using finite difference method in a curvilinear coordinate system. Different time-marching schemes are employed for the morphological computation under unidirectional and oscillatory conditions. It is found that vortex motions within the trench play an important role in the trench development.
Books on the topic "Underwater pipelines Hydrodynamics"
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Jørgen, Fredsøe, ed. Hydrodynamics around cylindrical structures. Singapore: World Scientific, 1997.
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Hydrodynamics around cylindrical strucures. Singapore: World Scientific Publishing, 2007.
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Fredsoe, Jorgen, and B. Mutlu Sumer. Hydrodynamics Around Cyclindrical Structures (Advanced Series on Ocean Engineering). World Scientific Publishing Company, 2006.
Find full textBook chapters on the topic "Underwater pipelines Hydrodynamics"
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Sills, N. V. "Hydrodynamic Excavation — Recent Experience in Pipeline and Cable De-Burial, Trenching and Backfilling and Large Scale Seabed Site Clearance." In Advances in Underwater Technology, Ocean Science and Offshore Engineering, 149–75. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1178-2_9.
Full textConference papers on the topic "Underwater pipelines Hydrodynamics"
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Li, Xin, Rubo Dong, Qiao Jin, and Jing Zhou. "Hydrodynamic Force Model on Free Spanning Pipeline Subjected to Seismic Excitations." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57081.
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Firstly, a series of model tests of free spanning submarine pipeline are carried out on an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. Hydrodynamic forces imposed on the span of submarine pipeline due to different direction excitations are studied. Secondly, finite element method on the base of the theory of interaction between fluid and structure is utilized to analyze the dynamic response of free spanning submarine pipelines subjected to earthquakes. Thirdly, based on Morison equation an improved hydrodynamic force model considering the effects of seismic exciting directions is proposed. Discretized equations of motion derived from the improved Morison equation is employed to analyze the dynamic response of free spanning submarine pipelines subjected to earthquakes. FE model is established to simulate the above experimental conditions. Finally, the comparison of numerical results with experimental results shows that the improved hydrodynamic force model could satisfactorily predict dynamic response on the free spanning submarine pipelines subjected to earthquakes.
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Pratikto, Widi Agoes, Raditya Danu Riyanto, Silvianita, Rendatiyarso Laksono, Muhammad Ilham Maulana, Wetta Inggrid Sari, Abiyani Choirul Huda, and Liany Ayu Catherine. "Evaluation of Underwater Pipeline Design Criteria Due to Safety Requirement based Hydrodynamic and External Load." In The 7th International Seminar on Ocean and Coastal Engineering, Environmental and Natural Disaster Management. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0010047000300036.
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Amir Hosseini, Mohammad Khalaj, Mohammad Banae, and Ali Meghdari. "A Composite Rigid Body Algorithm for Modeling and Simulation of an Underwater Vehicle Equipped With Manipulator Arms." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51503.
Full textAbstract:
In this paper modeling and simulation of an underwater vehicle equipped with manipulator arms, using Composite Rigid Body (CRB) algorithm will be discussed. Because of increasing need to Unmanned Underwater Vehicles (UUVs) in oil and gas projects in Persian Gulf, for doing operations such as inspection of offshore jackets, subsea pipelines and submarine cables and also pre installation survey and post laid survey of submarine pipelines and cables, design and construction of “SROV” was developed in Sharif University of Technology, and at design stage behavior of underwater vehicles was studied. In this paper, an efficient dynamic simulation algorithm is developed for an UUV equipped with m manipulators that each of them has N degrees of freedom. In addition to the effects of mobile base, the various hydrodynamic forces exerted on these systems in an underwater environment are also incorporated into the simulation. The effects modeled in this work are added mass, viscous drag, fluid acceleration, and buoyancy forces. For drag forces, the emphasis here is on the modeling of the pressure drag. Recent advances in underwater position and velocity sensing enable real-time centimeter-precision position measurements of underwater vehicles. With these advances in position sensing, our ability to precisely control the hovering and low-speed trajectory of an underwater vehicle is limited principally by our understanding of the vehicle’s dynamics and dynamics of the bladed thrusters commonly used to actuate dynamically-positioned marine vehicles. So the dynamics of thrusters, are developed, and an appropriate mapping matrix dependent on the position and orientation of the thrusters on the vehicle, is used to calculate resultant forces and moments of the thrusters on the center of gravity of the vehicle. It should be noted that hull-propeller and propeller-propeller interactions are considered in the modeling too. Finally the results of the simulations, for an underwater vehicle equipped with one 2 DOFs manipulator, are presented and discussed in details.
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Khandelwal, Prateek, Rajeev K. Jaiman, James Evon D’Souza, and Chan Keet Mak. "Direct Numerical Simulations of Wall Proximity Effect on Single and Tandem Cylinders." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23649.
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Subsea pipelines placed at or near the seabed are exposed to waves and underwater currents. The unstable seabed, irregular terrain, erosion of sediments or installation procedures may lead to free span in sections along the length of pipelines. This problem can be explained in simplified terms as a cylinder near an impermeable wall subjected to boundary layer based shear flow. It is common practice to use fixed cylinder hydrodynamic coefficients (drag, lift, and interia) to calculate the pipeline stability with the assumption that the pipeline is either trenched or lying on the seabed. However, due to the gap between the pipe and the seabed, the force coefficients have a strong dependence on the relative gap. In this paper, a moving wall is considered rather than a fixed wall to avoid the confusing interaction of wall boundary layer and thus focus completely on wall proximity effects to evaluate the lift and drag forces. In particular, the wall-induced lift force is due to two competing mechanisms in subsea pipelines. First, the vorticity generated at the surface of the cylinder cross-section advects and diffuses downstream. The presence of a nearby wall breaks the axisymmetry of the wake vorticity distribution. The resulting induced velocity also breaks the symmetry and results in an effective lift force that tends to move the pipeline away from the wall. Second, from inviscid theory, one can argue that the flow relative to the cylinder will accelerate faster in the gap between the cylinder and the wall. The resulting low pressure in the gap will induce a lift force directed toward the wall. In the first part, we focus on the wall-induced lift force in the finite Reynolds number regime using a Spectral Element method to perform direct numerical simulations (DNS) with high accuracy. The effects of gap ratio will be investigated in detail to characterize the oscillating forces on the cylinder. In the second part, this paper will focus on studying how seabed can affect two tandem cylinder arrangements as a function of spacing and the interaction of wall-induced forces with the wake dynamics between the two cylinders.
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Hsu, Ching-Yu, and Chan-Yung Jen. "The Transient Response of Imperfect Thin-Walled Stiffened Cylindrical Shell Exposed to Side-On Underwater Explosion." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79018.
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The thin-walled stiffened cylindrical shells are usually applied in a submarine which takes the external pressure load, or in a boiler, pressure vessel or pipeline system which takes the internal pressure load. The thin-walled stiffened cylindrical shells under hydrodynamic loading are very sensitive to geometrical imperfections. This study is investigating an imperfect thin-walled stiffened cylindrical shell (out-of-round ratio is ψ = 2%) at a depth of 50m below the water level to see how it withstands sideward TNT 782 kg underwater explosion loading so as to understand its structural transient response. ABAQUS finite element software is used as an analysis tool in the current study, meanwhile, during the analysis process, the Fluid-Structure Interaction (FSI) condition is employed. The structural transient response results of stress and displacement time history of the imperfect thin-walled stiffened cylindrical shell can be used as a reference for the anti-underwater explosion analysis and design of future submersible vehicles, pressure hulls or related structural designs.
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Li, Zhong, Rajeev K. Jaiman, Mun Yew Daniel Tham, and Boo Cheong Khoo. "Two-Dimensional Numerical Simulations of Wall Proximity Effect on Cylinders." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41639.
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In the oil and offshore industry, it is a common phenomenon that subsea pipelines placed on or in the proximity of the seabed are exposed to underwater waves and currents. Free spanning in sections along the length of pipeline frequently results from the erosion of sediments or the irregular terrain. This scenario can be modelled by a much more simplified set-up, where a circular cylinder situated near a plane wall is subjected to the oncoming flows. In this case, unlike the well-studied isolated cylinder, the hydrodynamic forces exerting on the near-wall cylinder will depend largely upon on the gap between the wall and the cylinder itself. In this work, flows around a stationary and a freely vibrating two-dimensional circular cylinder near a plane boundary are numerically simulated using the Immersed Interface Method (IIM) and Finite Element Method (FEM) with Arbitrary Lagrangian-Eulerian (ALE) approach, respectively. In the case of a stationary cylinder, instead of a fixed wall, a moving wall with no-slip boundary is considered in order to avoid the complex involvement of the boundary layer and to focus only on the shear-free wall proximity effects in evaluating the lift and drag forces in the low Reynolds number regime (Re ≤ 200), with the aim of validating our IIM solver since it is the first time to apply IIM in solving flows past a near-wall cylinder. The gap ratio e/D is typically taken from 0.1 to 2.0 in this part of studies, where e denotes the gap between the cylinder and the wall and D denotes the diameter of the cylinder. The key findings are that the mean drag coefficient increases and peaks at e/D = 0.5 with the increase of e/D and keeps decreasing from e/D = 0.5 to e/D = 2.0, while the mean lift coefficient decreases monotonically with the increase of e/D. In the case of the freely vibrating cylinder in both transverse and in-line directions, the fixed wall is used to include the shear-layer effect from the bottom wall in considering the near-wall vortex-induced vibration (VIV) by using FEM with ALE approach. It can be concluded from our observations that when the cylinder is brought closer to the wall from e/D = 10.0 to e/D = 0.75, the peak transverse displacement amplitude decreases, while the peak in-line displacement amplitude increases, by greater than 20 times that of an isolated cylinder.