Mechanisms of soil flow during submarine slide-pipe impact

Sahdi, Fauzan; Gaudin, Christophe; Tom, Joe G.; Tong, Feifei

doi:10.1016/j.oceaneng.2019.05.061

Cited by 22 publications

(4 citation statements)

References 14 publications

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“…As explained in detail in Fan et al (2021), there are two characteristic zones that can be identified from the flow streamlines: the low-velocity zone near the seabed (or seabed boundary layer, marked in green, where the velocity is smaller than the free-stream velocity v0; D r a f t the thickness of which is denoted as δseabed) and high-velocity zones at both upper and lower sides of the pipeline (marked in red, where the velocity is larger than v0; the dimension of which is denoted as Ra). In addition, a boundary layer may also form near the surface of the pipeline (marked in blue) and slide flow separation may occur at the rear of the pipeline (Sahdi et al 2019). The thickness of this boundary layer is, however, much less compared to that of the high-velocity zone.…”

Section: Flow Characteristics During Slide Mass-pipeline Interactionmentioning

confidence: 99%

Evaluation of horizontal submarine slide impact force on pipeline via a modified hybrid geotechnical – fluid dynamics framework

et al. 2022

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There are situations in offshore energy development where potential impact forces between submarine slides and pipelines need to be estimated. The horizontal slide-pipeline impact force, parallel to the main travel direction of the sliding mass and normal to the pipeline axis, is generally dominant compared to other force components, and hence of particular concern. In practice, pipelines may be suspended at varying distances above the seabed (gap) and existing methods do not consider how this will affect the horizontal slide-pipeline forces. This paper investigates the effects of pipeline-seabed gap and pipeline diameter on the horizontal slide-pipeline impact force via 181 computational fluid dynamics (CFD) simulations at Reynolds numbers of 0.36 - 287. Results show that variation in the pipeline-seabed gap and pipeline diameter alters the slide mass flow behavior as it flows past the pipeline and hence the impact force when the pipeline-seabed gap is below a critical value. A modified hybrid geotechnical-fluid dynamics framework for estimating the horizontal impact force is proposed by considering the effects of the pipeline-seabed gap and pipeline diameter, which is validated with existing experimental datasets.

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Section: Flow Characteristics During Slide Mass-pipeline Interactionmentioning

confidence: 99%

Evaluation of horizontal submarine slide impact force on pipeline via a modified hybrid geotechnical – fluid dynamics framework

et al. 2022

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“…4 with C D = 0.4 and N H = 13.0 fits the CFD (computational fluid dynamics) simulation results on the interaction of clay-rich debris and a suspended pipeline from Zakeri (2009b). Randolph and White (2012) and Sahdi et al (2019) argued that the first term is significant when Re non − Newtonian >~10. However, it should be noted that the above studies were based on clay-rich material.…”

Section: Landslidesmentioning

confidence: 66%

Ultimate lateral pressures exerted on buried pipelines by the initiation of submarine landslides

Zhang

Askarinejad

2021

Landslides

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Submarine slope instabilities are considered one of the major threats for offshore buried pipelines. This paper presents a novel method to evaluate the ultimate pressure acting on a buried pipeline during the liquefaction of an inclined seabed. Small-scale model tests with pipes buried at three different embedment ratios have been conducted at an enhanced centrifugal acceleration condition. A high-speed, high-resolution imaging system was developed to quantify the soil displacement field of the soil body and to visualize the development of the liquefied zone. The measured lateral pressures were compared with the hybrid approach proposed for the landslide–pipeline interaction in clay-rich material by Randolph and White (2012) and Sahdi et al. (2014). The hybrid approach is proved to be able to predict later pressures induced by the movement of (partially) liquefied sand on buried pipelines. It is found that the fluid inertia (fluid dynamics) component plays an important role when the non-Newtonian Reynolds number >~2 or the shear strain rate > 4.5 × 10−2 sec−1.

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“…In recent years, the computational fluid dynamics (CFD) simulation approach has been widely used in the studies of submarine slide motion (e.g., Gauer et al, 2005;Acosta et al, 2017;Fan et al, 2022a;Fan et al, 2022b) and its interaction with structures (e.g., Zakeri et al, 2009;Zakeri and Hawlader, 2013;Liu et al, 2015;Fan et al, 2018;Fan et al, 2019;Qian and Das, 2019;Sahdi et al, 2019;Fan et al, 2020a;Guo et al, 2021;Guo et al, 2022), due to the numerical solution stability and speed advantages on the multi-phase coupled flow field. To reproduce the influence of submarine slides on submerged floating tunnels in the underwater environment, the ANSYS-CFX numerical software based on the CFD simulation approach is employed in this study.…”

Section: Cfd Simulation Approach and Setupmentioning

confidence: 99%

Feasibility of submerged floating tunnel with polygonal cross-sections — investigation from a viewpoint of submarine slide hazards

Fan

et al. 2023

Front. Mar. Sci.

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Recently, submerged floating tunnels have generated a lot of interest due to their unique cross-water traffic benefits. However, the destructive threat of submarine slide hazards was not fully considered in the design scheme of submerged floating tunnels, in particular to the feasibility of applying various cross-section forms on land to submerged floating tunnels under that hazard influence. This study mainly investigates the load effect of submerged floating tunnels with polygonal cross-sections (comprising three types: square, hexagon, and octagon) under the impact of submarine slides, via a computational fluid dynamics (CFD) approach. Results show that the impact forces produced by submarine slides on submerged floating tunnels are significant (e.g., submarine slides with a velocity of 4 m/s may produce a force level near 1×105 N/m), where the horizontal impact force components should be given priority consideration based on the general working environment of submerged floating tunnels. Compared with typical circle tunnels, polygonal tunnels suffer higher impact forces, and the polygonal types with fewer edges show a greater impact force. Finally, a simplified force evaluation approach for the submerged floating tunnel with polygonal cross-sections is proposed for guiding the relevant engineering design.

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Mechanisms of soil flow during submarine slide-pipe impact

Cited by 22 publications

References 14 publications

Evaluation of horizontal submarine slide impact force on pipeline via a modified hybrid geotechnical – fluid dynamics framework

Evaluation of horizontal submarine slide impact force on pipeline via a modified hybrid geotechnical – fluid dynamics framework

Ultimate lateral pressures exerted on buried pipelines by the initiation of submarine landslides

Feasibility of submerged floating tunnel with polygonal cross-sections — investigation from a viewpoint of submarine slide hazards

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