Wave interaction with a submarine pipeline in clayey soil due to random waves
TL;DR: In this article, the wave pressure and uplift force due to random waves on a submarine pipeline (resting on bed, partially buried and fully buried) in clayey soil are measured.
About: This article is published in Ocean Engineering.The article was published on 2005-09-01. It has received 21 citations till now. The article focuses on the topics: Submarine pipeline & Wave height.
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TL;DR: In this article, a flexible rubber plate was placed between the submarine pipeline and bed, while the rigid spoiler was attached to the top of the pipe to enhance the scour depth and extent.
Abstract: This paper presents results from laboratory experimental model studies investigating scour by waves around a pipeline attached to a flexible rubber plate or rigid spoiler. The rubber plate was placed between the submarine pipeline and bed, while the rigid spoiler is attached to the top of the pipe. The scour around pipelines with and without a rubber plate or a rigid spoiler under regular and irregular waves was observed and measured for a range of pipe sizes, wave amplitudes and frequencies, and the length of the plate/height of the spoiler. The experiments reveal that although the rigid spoilers can enhance the scour depth and extent (thus accelerating the self-burial of the pipe), they also have significant influence on both the upstream and downstream bed topography as sand ripples and dunes are formed. On the other hand, the rubber plates cannot only significantly increase the scour depth but also have little effect on the upstream and downstream bed. The experiments show that when the length of the plate is about 1.5 times the pipe size, it provides the optimum performance in terms of the largest scour depth while restricting the impact on nearby beds for the parameters investigated in this study.
31 citations
TL;DR: In this paper, the joint effect of solitary waves and background currents on the pipelines is numerically studied by using a numerical wave tank developed with a free surface tracking approach and the immersed boundary method.
30 citations
TL;DR: In this article, a numerical model for seabed response around a pipeline in a trenched layer due to random waves is established, where three wave spectra including the JONSWAP spectrum, Bretchneider-Mitsuyasu spectrum and Pierson-Moscowitz spectrum are considered in the present model for the simulation of random waves.
14 citations
TL;DR: In this article, a numerical model for random wave-induced seabed response is established based on Longuet-Higgins random wave theory and finite element method, which is treated as poroelastic medium and characterized by Biot's partly dynamic equations.
Abstract: Research on the response of random wave on offshore structures has received great deal of attention of many researchers and engineers in the design of marine structures. Most previous investigations have been limited to the regular waves. In this paper, based on Longuet–Higgins random wave theory and finite element method, a numerical model for random wave-induced seabed response is established. The seabed is treated as poroelastic medium and characterized by Biot’s partly dynamic equations (u–p model). The JONSWAP spectrum is adopted in Longuet–Higgins model, which is based on the cumulative superposition of linear diffraction solution. Based on the numerical results, the effects of random wave on seabed response are investigated by comparing with the corresponding Stokes wave and cnoidal wave. Then, a parametric study is conducted to examine the effect of wave and soil characteristic on the seabed.
12 citations
Cites background from "Wave interaction with a submarine p..."
...Kumar, Neelamani, and Rao (2005) measured the wave pressure and uplift force due to random waves on a submarine pipeline in clayey soil....
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TL;DR: A movable-bed physical model has been used to investigate the coastal erosion of an abandoned section of the Huanghe (Yellow) River Delta as mentioned in this paper, and the experimental results indicate that the volume of deposition was about half that of the erosion.
Abstract: The erosion mechanisms of abandoned coastal section are understood detailedly by flume experiment, which play an important role to the offshore engineering facilities. A movable-bed physical model has been used to investigate the coastal erosion of an abandoned section of the Huanghe (Yellow) River Delta. The theory of physical scale models is discussed and a method for constructing the representative seabed section is developed. The results indicate that during the period initially after the abandonment of the delta the entire bed experienced rapid erosion because the seabed was steep and prone to liquefaction that resulted from storm wave action. After this initial period, a balance of erosion and accretion was established, and the beach profile equilibrated with a point of balance present on the profile. The experimental results indicate that the volume of deposition was about half that of the erosion. Wave action may also induce significant stratal changes through its interaction with the soft seabed. The major morphological features developed in the model delta section were found to be qualitatively comparable with those observed in the prototype. A distorted modeling law that maintains the similarity of the modeled and prototype equilibrium beach profiles is proposed. Experimental results show that the distorted modeling is able to reproduce the beach-face slope in nature, and the model also successfully reproduced three historical evolutionary stages of erosion.
5 citations
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TL;DR: In this paper, an analytical model is developed for estimating the pore pressure in the soil and the resulting pressure force on buried pipelines, assuming that the seabed is rigid, homogeneous, and porous with isotropic permeability.
Abstract: Ocean waves induce dynamic pressure responses in permeable seabeds which result in dynamic loads on buried pipelines. An analytical model is developed for estimating the pore pressure in the soil and the resulting pressure force on buried pipelines. It is assumed that the seabed is rigid, homogeneous, and porous with isotropic permeability, that the pore water is incompressible, that fluid flow in the soil is modeled by Darcy's Law, and that the seabed is infinitely deep. A solution is developed for a circular, rigid pipeline using conformal mapping techniques. The solution is compared with the results of both small and large‐scale tests; reasonable agreement is obtained for the small‐scale tests. Wave‐induced seepage forces are evaluated by integrating the pressure distribution over the pipe surface. The magnitude of the force remains constant but the direction rotates around the cylinder once with the passage of each wave. This force may be of sufficient magnitude to be an important consideration in the...
64 citations
TL;DR: In this paper, the wave-induced cyclic pore-pressure response of a seabed in the vicinity of a submarine pipeline was investigated. And the question of perturbation effects affecting the wave induced pore pressure field by the presence of a stiff and impermeable body of the submarine pipeline is analyzed thoroughly.
41 citations
TL;DR: In this paper, the hydrodynamical force of an undisturbed seabed to water waves is calculated using complex function theory and the technique of conformal mapping, and a good agreement is obtained with existing solutions.
32 citations
TL;DR: In this paper, the authors used boundary integral equation method (BIEM) to estimate the wave-induced pressure on a pipeline in a two-dimensional domain, assuming that the soil structure and fluid are incompressible.
Abstract: Wave‐induced pressures are an important design consideration for oil and natural gas pipelines buried in the marine environment. Realistic problems are three‐dimensional in nature and involve waves approaching the buried pipeline at oblique angles and special pipeline geometries. For fluid flow in a sandy soil where liquefaction does not occur and fluid acceleration terms are negligible, Darcy's law can be used. Assuming that the soil structure and fluid are incompressible, results will show the wave‐induced pressure in the domain being governed by the Laplace equation with associated boundary conditions on the domain boundaries. The pressure distribution on the pipeline is obtained using the boundary integral equation method (BIEM). The BIEM is economical because the computations are performed only on the two‐dimensional surface boundaries of the solution domain rather than throughout the entire three‐dimensional domain. The first problem analyzed is the two‐dimensional case where the pipeline is paralle...
31 citations
TL;DR: In this paper, a laboratory investigation of wave forces induced by a regular train of waves on a large pipeline resting on the bed and at various clearances from the bed is presented from considerations of dimensional analysis.
10 citations