Scour at Submerged Cylindrical Obstacles under Steady Flow

Dey, Subhasish; Raikar, Rajkumar V.; Roy, Abhishek

doi:10.1061/(asce)0733-9429(2008)134:1(105)

Cited by 71 publications

(39 citation statements)

References 11 publications

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“…The protrusion of a structure constructed in a riverbed or on the lateral bank in the main channel of a river reduces the width of the water course and disturbs the flow and sediment transport (Chen et al 2011(Chen et al , 2012. The flow at the upstream face of a structure is accelerated as it moves past the obstacle, creating a trailing vortex over the structure and wake vortices near the bed at the downstream face (Dey et al 2008;Lim 1997;Liu and Shen 2008). The presence of a solid structure strongly induces 3-D flow (Chen et al 2011(Chen et al , 2012.…”

Section: Instrumentation Techniques and Feasibilitymentioning

confidence: 99%

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Tiwari

Sharma

2015

Appl Water Sci

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This research paper focuses on the need of turbulence, instruments reliable to capture turbulence, different turbulence parameters and some advance methodology which can decompose various turbulence structures at different levels near hydraulic structures. Small-scale turbulence research has valid prospects in open channel flow. The relevance of the study is amplified as we introduce any hydraulic structure in the channel which disturbs the natural flow and creates discontinuity. To recover this discontinuity, the piano key weir (PKW) might be used with sloped keys. Constraints of empirical results in the vicinity of PKW necessitate extensive laboratory experiments with fair and reliable instrumentation techniques. Acoustic Doppler velocimeter was established to be best suited within range of some limitations using principal component analysis. Wavelet analysis is proposed to decompose the underlying turbulence structure in a better way.

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Section: Instrumentation Techniques and Feasibilitymentioning

confidence: 99%

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Tiwari

Sharma

2015

Appl Water Sci

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“…Such immovable obstruction embedded in the sediment bed restricts the area of flow in a stream channel. Water interacts with the upstream edge of the obstruction causing an increase in velocity around the sides accompanied by the development of various kinds of vortices like horseshoe vortex, wake vortex for emerged pier-like structures and trailing vortex in addition developed at the top of such obstructions for submerged case (Ettema et al 2006;Tsutsui 2008;Dey et al 2008). Scour occurs when fluid flow induced shearing stresses on the sand bed surface reach such values that exceed the shearing strength i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Dey et al (2008) introduced a submerged factor in determining the scour depth and its relation to the horseshoe vortex circulations for submerged bridge piers. Herget (2011, 2012) developed a simple analytical approach based on the obstacle Reynolds and Froude numbers to determine the local scour around submerged obstacles with various submerged factors in the fluvial environment.…”

Section: Introductionmentioning

confidence: 99%

Spacetime dynamics of bed forms due to turbulence around submerged bridge piers

Sarkar

Chakraborty

Mazumder

2014

Stoch Environ Res Risk Assess

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This work presents a study of spatiotemporal changes of scour-holes around sand embedded submerged circular and non-circular cylinders with associated turbulence properties and aims at analyzing the contribution of each quadrant event to the Reynolds shear stress. Experiments were carried out using submerged circular, elliptical, square and triangular cylinders of same length having flowfacing sides as the cylinder diameter with a common submergence ratio of 0.6. It is evident that upstream scour depth was maximum for the circular cylinder and minimum for the elliptical one. Interestingly, side-wise scouring rate was significant for elliptical cylinder. The maximum deposition region was formed at the downstream of the triangular cylinder case; and for the square cylinder, interestingly quite largest sediment accumulations occurred at the two sides about the centerline. The bed elevation spectra for all cases in downstream scour and deposition region showed comparatively higher spectral slopes, where positive bed slopes were generated except for the square cylinder case. In the near-bed region of upstream scour hole, the occurrence of probabilities were higher for sweeping events and it was less for the elliptical cylinder, where the bed was minimum negatively sloped, compared to other cylinders. In the downstream scoured location of the elliptical cylinder, where comparatively lower bed elevation was formed and the bed was negatively sloped, mostly the ejections were the occurring events near the bed region. However, for the other three cases with positive bed slopes, sweeping events were the dominating in near-bed region.

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“…Unfortunately, studies on local scour at submerged obstacles fully exposed to flow are scarce (e.g. Shamloo 1997, Shamloo et al 2001, Dey et al 2008. Bridge scour equations fail if applied to submerged obstacles, as was demonstrated by Herget (2005) or Shamloo (1997) for scour holes around submerged obstacles in the field and laboratory, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…First, an appropriate analytical approach is presented, which is then tested against own flume experiments. The model is finally validated using a data set of Dey et al (2008) and extended to prototype conditions by integrating a data set of Sheppard et al (2004).…”

Section: Introductionmentioning

confidence: 99%

Obstacle-Reynolds-number based analysis of local scour at submerged cylinders

Euler

Herget

2011

Journal of Hydraulic Research

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A simple process-based, analytical approach is developed and validated herein to determine the local scour at obstacles in the fluvial environment. It is based on the obstacle Reynolds and Froude numbers. Clear-water flume experiments were conducted to investigate the local scour depths at submerged cylinders in coarse uniform sand. The resulting scour depths were correlated with an analytical model and validated with two data sets on local scour at submerged and emergent cylinders. The size of the projected frontal obstacle area in relation to the mean flow velocity has a significant effect on the scour hole shape and depth. A power law function is derived that satisfactorily describes the present scour depth data. The approach is limited to nearequilibrium clear-water scour, uniform sediment and excludes particle density effects.

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Scour at Submerged Cylindrical Obstacles under Steady Flow

Cited by 71 publications

References 11 publications

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Spacetime dynamics of bed forms due to turbulence around submerged bridge piers

Obstacle-Reynolds-number based analysis of local scour at submerged cylinders

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