Clear-water scour depth below underwater pipelines

Dey, Subhasish; Singh, Navneet P.

doi:10.1016/j.jher.2007.07.001

Cited by 39 publications

(12 citation statements)

References 11 publications

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“…Our result, namely the decrease in scour depth due to US, is in agreement with the results of Sarkar and Dey (2007) and Dey and Singh (2007). However, this result is in disagreement with the results of the studies of Cheng and Chiew (1998a, b;1999), Yang (2013), and Dey and Sarkar (2007), who stated that the US can increase the scour depth.…”

Section: Applying Upward Seepagesupporting

confidence: 62%

“…Here, a brief review of the former is given. Dey and Singh (2007) studied the scour depth downstream of an underwater pipeline and showed a graphical relationship between the non-dimensional scour depth and dimensionless seepage velocity. Their results revealed that the scour depth is smaller in the presence of US, with a maximum reduction of about 34% when the dimensionless velocity was equal to 0.0015.…”

Section: Introductionmentioning

confidence: 99%

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Scour Downstream of Grade Control Structures under the Influence of Upward Seepage

2016

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The installation of free falling jet grade control structures has become a popular choice for river bed stabilization. However, the formation and development of scour downstream of the structure may lead to failure of the structure itself. The current approaches to scour depth prediction are generally based on studies conducted with the absence of upward seepage. In the present study, the effects of upward seepage on the scour depth were investigated. A total of 78 tests without and with the application of upward seepage were carried out using three different sediment sizes, three different tailwater depths, four different flow discharges, and four different upward seepage flow discharge rates. In some tests, the three-dimensional components of the flow velocity within the scour hole were measured for both the cases with and without upward seepage. The scour depth measured for the no-seepage results compared well with the most accurate relationship found in the literature. It was found that generally the upward seepage reduced the downward velocity components near the bed, which led to a decrease in the maximum scour depth. A maximum scour depth reduction of 49% was found for a minimum tailwater depth, small sediment size, and high flow discharge. A

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Section: Applying Upward Seepagesupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Scour Downstream of Grade Control Structures under the Influence of Upward Seepage

2016

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“…where is the friction coefficient, which can be obtained using the Colebrook-White equation ( Dey and Singh, 2007):…”

Section: Prediction Of Scour Depthmentioning

confidence: 99%

Improving the prediction of scour around submarine pipelines

Zhang¹,

Shi²,

Guo³

et al. 2016

Proceedings of the Institution of Civil Engineers - Maritime En

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Local scour around submarine pipelines can affect the stability of the pipeline. The accurate estimation of the scour around submarine pipelines has been a hot topic of research among marine engineers. This paper presents results from a numerical study of clear-water scour depth below a submarine pipeline for a range of the steady flow conditions. The flow field around the pipeline under scour equilibrium condition is numerically simulated by solving the Reynolds-Averaged Navier-Stokes (RANS) equations with the standard k-ε turbulence closure. The flow discharge through the scour hole for various flow conditions is investigated. The results are used to establish the relationship between the flow discharge and the maximum scour depth. Incorporated with the Colebrook-White equation, the bed shear stress is obtained and an iterative method is proposed to predict the scour depth around the submarine pipeline. The calculated scour depths using the present method agree well with the laboratory measurements, with the average absolute relative error being smaller than that using previous methods, indicating that the proposed method can be used to predict the clear-water scour around the submarine pipeline with satisfactory accuracy.

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“…include: mean flow velocity of the approach flow , V (on the assumption of a fully developed boundary layer); undisturbed approach flow depth, y,,; density of water, p; density of the sediment, ps; viscosity of water, j1; channel width, B; median grain size of bed material, d 50 ; diameter of the pipeline, D ; pipeline embedment, e, where e = vertical distance between the bottom of the pipeline to the undisturbed sediment bed level (In this study, a positive value of e means that the pipeline is buried in the sediment bed); and acceleration due to gravity g (Moncada-M and Aguirre-Pe, 1999). Dey and Singh (2008) have reported other variables, which also could influence the pipeline scouring such as geometric standard deviation of the bed sediment, CT g and shape of the pipeline cross section. In this study, CT g , however, is a dimensionless constant and the shape of all pipeline models tested is circular.…”

Section: Figure 1 Top View Of a Scour Hole Dimensional Analysismentioning

confidence: 99%

Three-Dimensional Scour at Submarine Pipelines in Unidirectional Steady Current

Wu¹,

Chiew

2010

Scour and Erosion

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This paper presents results of an experimental study on 3-dimensional scour at submarine pipelines with uniform sediments under a unidirectional steady current. A dimensional analysis is first conducted to identify all the important nondimensional parameters. Laboratory experiments are then conducted to study the development of a 3-dirnensional pipeline scour hole under different sets of environmental conditions. The results are recorded and the corresponding propagation velocities of the free span calculated. The effects of four parameters on the propagation velocity are studied through the conduct of several groups of experiments; each of which exclusively focuses on one particular parameter. Moreover, the scour pattern under different combinations of environmental conditions is discussed to obtain an improved understanding on the mechanism of scour hole propagation at the span shoulder of pipelines.

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Clear-water scour depth below underwater pipelines

Cited by 39 publications

References 11 publications

Scour Downstream of Grade Control Structures under the Influence of Upward Seepage

Scour Downstream of Grade Control Structures under the Influence of Upward Seepage

Improving the prediction of scour around submarine pipelines

Three-Dimensional Scour at Submarine Pipelines in Unidirectional Steady Current

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