Turbulent Flow Structures and Scour Hole Characteristics around Circular Bridge Piers over Non-Uniform Sand Bed Channels with Downward Seepage

Chavan, Rutuja; Gualtieri, Paola; Kumar, Bimlesh

doi:10.3390/w11081580

Cited by 15 publications

(8 citation statements)

References 26 publications

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“…In order to explain the phenomenology of scouring, the flow dynamics and turbulence characteristics around bridge piers was studied thoroughly in the past and is still the object of intense investigation (i.e., [16,[19][20][21][22][23][24][25][26][27][28] among numerous studies). Flow dynamics and turbulence are often characterized by their turbulence intensity, Reynolds stress, and total kinetic energy, with several coherent structures that form when a free-surface flow hits a vertical structure.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Flow Structure around Cylindrical Bridge Piers in Pressure-Flow Conditions

Carnacina

Leonardi

Pagliara

2019

Water

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The emerging shift of extreme events, combined with an aging infrastructure and bridges, highlights the potential increase in the risk of damage and catastrophic failure of bridges with climate change. This article analyzes the behavior of the flow and turbulence features in proximity to bridge piers, at two different moments of the scour temporal evolution in free-surface and pressure-flow conditions. Bridge pressure-flow conditions occur when the water depth submerges a bridge deck during extreme events. A circular pier and two rectangular decks of different lengths were used for this research. All tests were carried out in clear water conditions at the sediment critical velocity. This paper studied first the rate of scour temporal evolution and scour morphologies. Second, velocity measurements were taken using a Nortek acoustic Velocimeter at 25 Hz sampling rate in both free-surface and pressure-flow conditions. The average three-dimensional flow velocities, turbulence intensities, Reynolds stress, and turbulent kinetic energy were studies for the cross section corresponding to the center of the pier. The results show that pressure flow conditions accelerate the scour rate. This rate approximately reaches twice the scour in free-surface conditions with a vertical contraction of about 17%. Flow and turbulence measurements clearly exhibit how, under pressure-flow conditions, the additional turbulence and accelerated velocity modifies the flow pattern and circulation, accelerating the scour evolution around the bridge base. While numerous studies exist for pier scour and turbulence in free-surface conditions, pressure flow conditions received limited attention in the past. These results provide essential information for understanding scour mechanisms and for facilitating the design of future structures to increase bridge safety and resilience.

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Section: Introductionmentioning

confidence: 99%

Characteristics of Flow Structure around Cylindrical Bridge Piers in Pressure-Flow Conditions

Carnacina

Leonardi

Pagliara

2019

Water

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“…This paper [31] presents the experimental results of the scour hole characteristics forming around single vertical pier sets on a non-uniform sand bed with and without downward seepage. Empirical equations for the evaluation of the scour hole characteristics such as the length, width, area, and volume, including the downward seepage parameter, are proposed and experimentally tested.…”

Section: Chavan Et Al Turbulent Flow Structures and Scour Hole Charac...mentioning

confidence: 99%

Experimental, Numerical and Field Approaches to Scour Research

Chiew

Lai

Link

2020

Water

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Scour, which represents a fascinating and complex engineering problem involving a number of physical mechanisms and interactions, has motivated a vast amount of research following different but complementary methodological approaches such as experimental, numerical, and field methods. Far from being completely understood, scour remains one of the main hazards for many structures such as bridges, submarine pipelines, offshore wind turbines, etc. Thus, scour is currently a very active field of research with important open questions that are unanswered and practical challenges to be tackled. This Special Issue aims to bridge knowledge gaps by collecting fourteen papers to provide a wide view of scour types and different research approaches, with innovative ideas and inferences.

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“…A vortex formation around bridge piers can be destructive by causing complex flow interactions and scouring at riverbed. There is a huge research interest among literature in the field of hydrodynamics around the flow obstruction [5,8,16,22,23,25,26,29,45,49]. Most researches have been conducted on the turbulent characteristics of flow over smooth and rough boundaries around single pier or obstruction [2,35,46,47], and fewer studies have been conducted on coherent flow structures to study the burst cycle dynamics and to understand the burst cycles correlation to flow [7,18,24,34].…”

Section: Introductionmentioning

confidence: 99%

Bursting phenomenon created by bridge piers group in open channel flow

Ikani

Taha

et al. 2023

Environ Fluid Mech

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Bridge pier is a common feature in hydraulic structure. Its impact to the river usually occurs in group form rather than single pier, so this challenging piers-group influence towards river hydraulics and turbulence needs to be explored. In this paper, the measurements were conducted using an Acoustic doppler velocimeter (ADV) to study velocities in three dimensions (longitudinal, transversal, and vertical). Based on the experimental data, we have observed reversed depth-averaged velocity vector after each pier in the group of three-pier. The analysis has been conducted on the contribution of each bursting event to Reynolds shear stress (RSS) generation, in order to identify the critical events and turbulence structures around the piers. In the upstream near-wake flow in the bed-wall layer, strong sweep and ejection events have been observed; while at downstream, sweeps were more dominant. The pattern of burst changed in the outer layer of flow, where ejections were more dominant. Furthermore, the contribution fractional ratio to RSS variation at hole size H = 0 indicates that sweeps and ejections were significantly generated at the near wake-flow in upstream.

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Turbulent Flow Structures and Scour Hole Characteristics around Circular Bridge Piers over Non-Uniform Sand Bed Channels with Downward Seepage

Cited by 15 publications

References 26 publications

Characteristics of Flow Structure around Cylindrical Bridge Piers in Pressure-Flow Conditions

Characteristics of Flow Structure around Cylindrical Bridge Piers in Pressure-Flow Conditions

Experimental, Numerical and Field Approaches to Scour Research

Bursting phenomenon created by bridge piers group in open channel flow

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