Research

Jump to: Review

18 pages, 4789 KiB

Open AccessArticle

Application of a Single Porous Basket as a Pier Scour Countermeasure

by Wei-Lin Lee, Chih-Wei Lu and Chin-Kun Huang

Water 2021, 13(21), 3052; https://0-doi-org.brum.beds.ac.uk/10.3390/w13213052 - 01 Nov 2021

Cited by 4 | Viewed by 1810

This paper presents a study on bridge pier protection with a single porous basket (SPB) in clear-water experiments. The SPB is a type of combined flow-altering countermeasure. The SPB was installed at a distance ahead of the protected pier. After a series of [...] Read more.

This paper presents a study on bridge pier protection with a single porous basket (SPB) in clear-water experiments. The SPB is a type of combined flow-altering countermeasure. The SPB was installed at a distance ahead of the protected pier. After a series of tests, the results showed that appropriate installation of the SPB was able to effectively adjust the flow pattern to reduce the down-flow motion and horseshoe vortex ahead of the pier. Dominant factors for the pier protection—considered for all tests—included the distance between the basket and pier, submerged depth of the basket, basket length, pier diameter, basket diameter, hole size, porosity, and the flow approaching angle. After evaluating these parameters through laboratory tests, the results of protection were optimized. In optimal conditions, the SPB was able to provide maximum pier protection and decrease the maximum scour depth by as much as 75.53%. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

16 pages, 12638 KiB

Open AccessArticle

The Phenomenological Theory of Turbulence and the Scour Evolution Downstream of Grade-Control Structures under Steady Discharges

by Jessica Di Nardi, Michele Palermo, Fabián A. Bombardelli and Stefano Pagliara

Water 2021, 13(17), 2359; https://0-doi-org.brum.beds.ac.uk/10.3390/w13172359 - 27 Aug 2021

Cited by 4 | Viewed by 1901

Abstract

A more complete understanding of scour mechanisms for flows downstream of grade-control structures, including their temporal evolution, has the potential to lead to improved predicting tools for design. To date, design equations have been mostly derived empirically, i.e., by parametric modelling (at [...] Read more.

A more complete understanding of scour mechanisms for flows downstream of grade-control structures, including their temporal evolution, has the potential to lead to improved predicting tools for design. To date, design equations have been mostly derived empirically, i.e., by parametric modelling (at generally-small scales) corresponding to specific structure configurations, and for limited ranges of hydraulic conditions. Although these approaches allowed different authors to propose many empirical and/or semi-empirical equations, they lack generality and may lead to incorrect estimations when applied outside their ranges of validity. First-principles-based methods with solid calibration and validation procedures can overcome these issues. Following recent theoretical advancements presented elsewhere by the last three authors, in this work we analyze and test the predictive capability of a scour evolution model based on the phenomenological theory of turbulence (PTT) by using a large dataset pertaining to different grade-control structures. Although the PTT model was developed (and validated) for scour evolution caused by oblique and vertical plunging jets, we show that its basic assumptions are still valid for the addressed low-head structures, encompassing rock structures, stepped gabion weirs, rock and bed sills, and others. Furthermore, we also provide interesting insights on scour evolution by contrasting the predicting capability of our model against experimental data by different authors for specific structures. Results of the comparison conclusively show that the PTT model has a general validity and represents a trustable tool to estimate scour evolution regardless of the structure configuration and hydraulic conditions. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

17 pages, 6659 KiB

Open AccessFeature PaperArticle

Experimental Analysis of Scour Features at Chevrons in Straight Channel

by Deep Roy, Simone Pagliara and Michele Palermo

Water 2021, 13(7), 971; https://0-doi-org.brum.beds.ac.uk/10.3390/w13070971 - 01 Apr 2021

Cited by 5 | Viewed by 2670

Abstract

Eco-friendly river restoration structures are used to create localized scour pools which serve as fish nurseries and promote biodiversity. In this category, chevrons are relatively new structures designed to maintain navigability in rivers. The scour hole formed in the wake region of chevrons [...] Read more.

Eco-friendly river restoration structures are used to create localized scour pools which serve as fish nurseries and promote biodiversity. In this category, chevrons are relatively new structures designed to maintain navigability in rivers. The scour hole formed in the wake region of chevrons can either act as a disposal site for dredged material or as a resting spot for different fish species. However, only few studies are present in the literature dealing with the scour mechanism due to chevrons. Therefore, this work aims to analyze the scour features at equilibrium, under different hydraulic conditions and transversal locations in a straight channel. Tests were conducted with both isolated and multiple chevrons in series arrangement. Scour morphology types were classified and their fields of existence were established as well. A detailed dimensional analysis was conducted, allowing us to identify the main parameters governing the scour phenomenon and derive a novel equivalent densimetric Froude number. Finally, empirical equations were developed to predict the maximum scour depth and length as well as the maximum dune height. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

17 pages, 8589 KiB

Open AccessFeature PaperArticle

Experimental Analysis of Structures for Trapping SARS-CoV-2-Related Floating Waste in Rivers

by Deep Roy, Simone Pagliara and Michele Palermo

Water 2021, 13(6), 771; https://0-doi-org.brum.beds.ac.uk/10.3390/w13060771 - 12 Mar 2021

Cited by 3 | Viewed by 2452

Abstract

Personal protection equipment (PPE, e.g., masks and gloves) related to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic may represent a significant source of riverine plastic pollution. Several studies were conducted to analyze plastic transport in rivers; however, apparently, none of them [...] Read more.

Personal protection equipment (PPE, e.g., masks and gloves) related to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic may represent a significant source of riverine plastic pollution. Several studies were conducted to analyze plastic transport in rivers; however, apparently, none of them systematically investigated the efficiency of countermeasures in trapping/stopping floating plastic and nonwoven fabric materials originating from the abovementioned PPE. To fill this gap of knowledge and considering the current importance of the topic, the present paper aims at investigating the efficiency of several structure configurations that can be located in both natural and artificial water bodies. To this end, two different efficiencies were defined, i.e., kinematic (for isolated structures) and trapping (for structures in series). Experimental results evidenced that both the kinematic and the trapping efficiencies increase with the Froude number. We also developed empirical equations, which may be applied for predicting the structure efficiency in limiting plastic transport in rivers. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

18 pages, 9497 KiB

Open AccessArticle

Investigation on the Water Flow Evolution in a Filled Fracture under Seepage-Induced Erosion

by Jianli Shao, Qi Zhang, Xintao Wu, Yu Lei, Xunan Wu and Zaiyong Wang

Water 2020, 12(11), 3188; https://0-doi-org.brum.beds.ac.uk/10.3390/w12113188 - 14 Nov 2020

Cited by 16 | Viewed by 2227

Abstract

Water inrush is a major geological hazard for safe mining and tunnel construction. For the water inrush channel containing mud, sand, and other sediments, it is difficult to predict the change of permeability and water surge, which makes disaster prevention difficult. As a [...] Read more.

Water inrush is a major geological hazard for safe mining and tunnel construction. For the water inrush channel containing mud, sand, and other sediments, it is difficult to predict the change of permeability and water surge, which makes disaster prevention difficult. As a typical water inrush channel, a filled fracture under seepage-induced erosion needs to be focused. In this work, a numerical model for the evolution of flow in a filled fracture under seepage-induced erosion was established, which included the seepage velocity, hydraulic erosion, and permeability of the filling medium. The effects of joint roughness coefficient (JRC) and homogeneity of the filling medium on the seepage evolution are discussed. The results showed that the fracture seepage properties experienced a non-linear change process, and the evolution can be divided into three phases: the slowly varying phase, the rapidly varying phase, and the stable phase. The increase of the JRC hindered the development in flow velocity and erosion. Compared with low homogeneous filling medium, pores in the high homogeneous filling medium were easier to expand and connect, and the seepage characteristics evolved faster. The model established in this study will help to understand the seepage evolution of filled fractures, and can be used to predict the permeability of filled fractures in engineering geology. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

12 pages, 1572 KiB

Open AccessArticle

An Examination of the Dependency between Maximum Equilibrium Local Scour Depth and the Grain Size/Structure Size Ratio

by Raphael Crowley, William Cottrell and Alexander Singleton

Water 2020, 12(11), 3117; https://0-doi-org.brum.beds.ac.uk/10.3390/w12113117 - 06 Nov 2020

Cited by 1 | Viewed by 1365

Abstract

This paper begins by demonstrating how the Florida Department of Transportation (FDOT) local scour equations take the ratio between grain size and structure size into account when computing equilibrium local scour depth and contrasts this with the well-known Colorado State University (CSU) equation [...] Read more.

This paper begins by demonstrating how the Florida Department of Transportation (FDOT) local scour equations take the ratio between grain size and structure size into account when computing equilibrium local scour depth and contrasts this with the well-known Colorado State University (CSU) equation that does not take sediment information into account. Then, a relatively recent empirical formulation from the J-L. Briaud research group for computing local equilibrium scour depth is presented that appears to take the structure size/grain size ratio into account indirectly. Next, a possible explanation for the dependency between local equilibrium scour depth and the structure/grain size ratio is presented that was originally developed by D. Max Sheppard in 2004. This explanation shows that superimposing the pressure gradient around a particle with the pressure gradient around a pile leads to the dependency between equilibrium scour depth and the grain size/structure size ratio. Finally, a new formulation for local equilibrium scour depth based upon turbulent energy spectrum decay is presented. This new formulation reduces the local scour problem to a problem whereby turbulent diffusivity must be better understood. However, this new formulation also appears to show a dependency between equilibrium scour depth and the grain size/structure size ratio. Overall, the analysis presented herein provides several reasons, explanations, and pieces of evidence to suggest that the grain/structure size ratio is an important parameter to consider when computing local equilibrium scour depth. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

Review

Jump to: Research

42 pages, 19633 KiB

Open AccessFeature PaperReview

A Review on Existing Methods to Assess Hydraulic Erodibility Downstream of Dam Spillways

by Yavar Jalili Kashtiban, Ali Saeidi, Marie-Isabelle Farinas and Marco Quirion

Water 2021, 13(22), 3205; https://0-doi-org.brum.beds.ac.uk/10.3390/w13223205 - 12 Nov 2021

Cited by 8 | Viewed by 4061

Abstract

In recent years, rock scouring or erosion downstream of dams has become an increasing dam safety concern. Several theoretical, semi-theoretical, semi-analytical and numerical methods can be used to assess the rock erosion in hydraulic structures. Semi-theoretical approaches determine the correlation between the erosive [...] Read more.

In recent years, rock scouring or erosion downstream of dams has become an increasing dam safety concern. Several theoretical, semi-theoretical, semi-analytical and numerical methods can be used to assess the rock erosion in hydraulic structures. Semi-theoretical approaches determine the correlation between the erosive intensity of fluid flow and the resistive capacity of rock. Such approaches establish the scour thresholds as a function of erosive intensity of water and several rock mass indices by using in situ data and a curve-fitting approach. In some studies, the excavatability index, initially developed for rock mass stability analysis, was used to analyse the rock mass resistance in hydraulic erodibility analysis. The effectivity and weight of the geomechanical parameters used are yet to be determined on the basis of the erodibility phenomenon. The semi-analytical methods are developed on the basis of the mechanical and hydraulic interaction of rock mass and water. Four methods developed by Bollaert et al. are important in determining the erodibility in the plunge pool, but they are not applicable in the case of spillways. They used the comprehensive fracture mechanics for closed-end joints, quasi-steady impulsion, and dynamic impulsion (DI) for blocky rock erosion. The application of these methods to each site is necessary to identify constants that are difficult to determine. Few numerical methods are available to assess the rock mass erosion in hydraulic structures. In the case of numerical methods, the erosive agent is indistinct, and the hydraulic hazard parameter on the spillway surface is almost challenging to apply. This study comprehensively reviews the mechanism of erosion and the methods for assessing the risk of potential rock mass erosion downstream of dams and hydraulic structures. The advantages and disadvantages of all methods are discussed and the potential future research directions in this domain are proposed. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

24 pages, 34001 KiB

Open AccessFeature PaperReview

Identification of Hydraulic Parameters Influencing the Hydraulic Erodibility of Spillway Flow Channels

by Aboubacar Sidiki Koulibaly, Ali Saeidi, Alain Rouleau and Marco Quirion

Water 2021, 13(21), 2950; https://0-doi-org.brum.beds.ac.uk/10.3390/w13212950 - 20 Oct 2021

Cited by 2 | Viewed by 2330

Abstract

The rock mass erosion of dam spillways, a phenomenon involving the interaction between the hydraulic load of water and the capability of the rock mass to resist its destruction, remains a critical safety issue. The erosion resistance of a rock mass can be [...] Read more.

The rock mass erosion of dam spillways, a phenomenon involving the interaction between the hydraulic load of water and the capability of the rock mass to resist its destruction, remains a critical safety issue. The erosion resistance of a rock mass can be estimated through several erodibility indices, including those of Kirsten, Pells or Bollaert. Several indices have been developed to link rock resistance to the hydraulic parameters of water, i.e., the hydraulic load applied on a rock mass. The developed indices use the average flow velocity, the average shear stress on the bottom of the flow channel, the stress applied to the internal joints of fractured rock mass, the dynamic impulse force, and the power dissipation of water to represent the erosive force of water. From these indices, several methods of assessing hydraulic erosion have been developed, and all use the threshold line concept. Nonetheless, several uncertainties are associated with these methods. This paper presents and discusses the various means of calculating the erosive force of water as a hazard parameter for predicting potential rock erosion. The representativeness of these approaches is also discussed, and we clarify nuances associated with each method. We then provide guidelines for future research aimed at improving estimates of the erosive force of the water within spillway flow channels. Full article

(This article belongs to the Special Issue Erosion Processes in Hydraulic Engineering)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Erosion Processes in Hydraulic Engineering

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI