Scour below submerged skewed pipeline

Azamathulla, Hazi Mohammad; Yusoff, Mohd Azlan Mohd; Hasan, Zorkeflee Abu

doi:10.1016/j.jhydrol.2013.11.058

Cited by 29 publications

(14 citation statements)

References 13 publications

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“…the flow condition did not change during scour). These investigations have included two-dimensional physical model experiments to measure the extent and rate of scour in steady current [1][2][3][4][5][6][7][8][9][10][11][12] waves [13][14][15] and combined waves and current [16,17]. The three-dimensional local scour below a rigid pipeline has also been investigated experimentally in steady current [18,19], waves and combined waves and current [20].…”

Section: Introductionmentioning

confidence: 99%

Scour below a subsea pipeline in time varying flow conditions

Zhang

Draper

Cheng

et al. 2016

Applied Ocean Research

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This paper presents results of an experimental investigation into the time scale of local scour and backfill for a subsea pipeline in changing flow conditions, modelled as two consecutive but different flow conditions and as uniformly increasing flow velocities. Unidirectional current flow, waves and combined waves and current flow are all considered. Based on the results of the experiments, effective time scales of the scour and backfill are quantified and algorithms to predict the scour process in changing flow conditions are derived by accumulating the effects of the different flow conditions. It is found that these algorithms may be used to predict the scour observed in the experimental data reasonably well.

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Section: Introductionmentioning

confidence: 99%

Scour below a subsea pipeline in time varying flow conditions

Zhang

Draper

Cheng

et al. 2016

Applied Ocean Research

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“…The behavior can be explained by analyzing the vortex system induced by the fluid-structure interaction, which is described in the following sections. Furthermore, it is possible to note that the resulting scour hole involves the area upstream to and beneath the cylinder, owing to a particular process also known as tunnel erosion [41], that is ascribed to seepage processes [2,42] and occurs when the ratio between the flow depth and the cylinder diameter is less than 3.5 [16]. The vortices due to the obstacle led to instabilities to the particles, moving them away.…”

Section: Longitudinal Bed Profilesmentioning

confidence: 99%

“…In all these cases, the 3D flow field is extremely complicated due to the separation and the creation of multiple vortices. However, the complexity is further exaggerated owing to the dynamic interaction between the flow and the movable bed [2]. Erosion may occur around the pipelines, causing a higher gap between it and the bed surface and, therefore, compromising their safety.…”

Section: Introductionmentioning

confidence: 99%

Turbulent Flow Field around Horizontal Cylinders with Scour Hole

Penna

Coscarella

Gaudio

2020

Water

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This study presents the results of an experimental investigation on the flow-structure interactions at scoured horizontal cylinders, varying the gap between the cylinder and the bed surface. A 2D Particle Image Velocimetry (PIV) system was used to measure the flow field in a vertical plane at the end of the scouring process. Instantaneous and ensemble-averaged velocity and vorticity fields, viscous and Reynolds stresses, and ensemble-averaged turbulence indicators were calculated. Longitudinal bed profiles were measured at the equilibrium. The results revealed that suspended and laid on cylinders behave differently from half-buried cylinders if subjected to the same hydraulic conditions. In the latter case, vortex shedding downstream of the cylinder is suppressed by the presence of the bed surface that causes an asymmetry in the development of the vortices. This implies that strong turbulent mixing processes occur downstream of the uncovered cylinders, whereas in the case of half-buried cylinders they are confined within the scour hole.

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“…One of the key factors for bridge stability is the scour around piers and abutments, which is caused by flowing water. Scour is a natural but complicated phenomenon in river engineering due to the three-dimensional flow separations around bridge elements, the natural bed forms, the existence of vegetation, and the complex natural flow conditions [1][2][3][4][5]. Recent surveys have shown that in a sample of about 500 bridges collapsed in the US since 1951, 60% of collapses were due to pier scour [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…Qi et al [5] performed a field scour analysis and came to the conclusion that the access allowance through the embankment and scour at bridge foundations are the main causes of bridge failure. Therefore, the estimation of the amount of scour is necessary for designing an economical and safe bridge structure [1,[8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Pier Scour Prediction in Non-Uniform Gravel Beds

Pandey

Oliveto

et al. 2020

Water

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Pier scour has been extensively studied in laboratory experiments. However, scour depth relationships based on data at the laboratory scale often yield unacceptable results when extended to field conditions. In this study, non-uniform gravel bed laboratory and field datasets with gravel of median size ranging from 2.7 to 14.25 mm were considered to predict the maximum equilibrium scour depth at cylindrical piers. Specifically, a total of 217 datasets were collected: 132 from literature sources and 85 in this study using new experiments at the laboratory scale, which constitute a novel contribution provided by this paper. From the analysis of data, it was observed that Melville and Coleman’s equation performs well in the case of laboratory datasets, while it tends to overestimate field measurements. Guo’s and Kim et al.’s relationships showed good agreements only for laboratory datasets with finer non-uniform sediments: deviations in predicting the maximum scour depth with non-uniform gravel beds were found to be significantly greater than those for non-uniform sand and fine gravel beds. Consequently, new K-factors for the Melville and Coleman’s equation were proposed in this study for non-uniform gravel-bed streams using a curve-fitting method. The results revealed good agreements between observations and predictions, where this might be an attractive advancement in overcoming scale effects. Moreover, a sensitivity analysis was performed to identify the most sensitive K-factors.

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Scour below submerged skewed pipeline

Cited by 29 publications

References 13 publications

Scour below a subsea pipeline in time varying flow conditions

Scour below a subsea pipeline in time varying flow conditions

Turbulent Flow Field around Horizontal Cylinders with Scour Hole

Pier Scour Prediction in Non-Uniform Gravel Beds

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