Flow Resistance of Rock Chutes with Protruding Boulders

Pagliara, Stefano; Chiavaccini, Pietro

doi:10.1061/(asce)0733-9429(2006)132:6(545)

Cited by 69 publications

(70 citation statements)

References 22 publications

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“…Step-pool nature-like fishway Most of hydraulic studies on SPNFs have focused on the evaluation of velocity, dissipated energy or friction factors (Pagliara and Chiavaccini, 2006;Wang and Hartlieb, 2011;Oertel and Schlenkhoff, 2012) and, there are no specific studies on discharge and discharge coefficients.…”

Section: 3mentioning

confidence: 99%

Villemonte's approach: a general method for modeling uniform and non-uniform performance in stepped fishways

Fuentes‐Pérez

García‐Vega

Sanz‐Ronda

et al. 2017

Knowl. Manag. Aquat. Ecosyst.

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-Stepped fishways are the most popular solutions to enable the free movement of fish fauna through weirs and dams. Given the flow variation of rivers throughout the year, successful fish migration through stepped fishways relies on the accurate discharge calculation and their modeling under variable scenarios. This study aims to propose a general method for flow and water level calculation of stepped fishways, unifying different findings in specialized literature. To achieve this purpose, the relation defined by Villemonte is used and tested under laboratory and field case studies. This study shows that the hydraulic behavior of a wide range of stepped fishway typologies can be explained based on a single equation, as well as the need of calibration of the coefficients involved in this equation for different subtypes. Furthermore, the proposed method enables the water level modeling under variable boundary conditions, which in turns allows the analysis of stepped fishways hydraulic performance under different river scenarios. The comparison of the hydraulic parameters in the fishways with the physical capacities and preferences of fish will contribute to the fulfillment of their main objective: allow free movement of fish fauna.Keywords: discharge coefficient / flow measurement / vertical slot fishway / pool and weir fishway / nature-like fishway Résumé -L'approche de Villemonte : une méthode générale de modélisation de la performance uniforme et non uniforme dans les échelles à poissons. Les échelles à poissons sont les solutions les plus populaires pour permettre la libre circulation de la faune piscicole à travers les seuils et les barrages. Compte tenu de la variation de débit des cours d'eau tout au long de l'année, la migration réussie des poissons par ces passes à poissons repose sur le calcul exact de la décharge et sa modélisation dans des scénarios variables. Cette étude a pour but de proposer une méthode générale de calcul du débit et du niveau d'eau des échelles à poissons, synthétisant différents résultats de la littérature spécialisée. Pour atteindre cet objectif, la relation définie par Villemonte est utilisée et testée dans des études de cas en laboratoire et sur le terrain. Cette étude montre que le comportement hydraulique d'une large gamme de typologies de poissons en gradins peut être expliqué sur la base d'une seule équation, avec besoin d'étalonnage des coefficients impliqués dans cette équation pour différents sous-types. De plus, la méthode proposée permet de modéliser le niveau de l'eau dans des conditions aux limites variables, ce qui permet, à son tour, d'analyser la performance hydraulique des passes de poissons en escaliers selon différents scénarios de rivières. La comparaison des paramètres hydrauliques dans les passes à poissons avec les capacités physiques et les préférences des poissons contribuera à la réalisation de leur objectif principal : permettre la libre circulation de la faune aquatique.Mots-clés : coefficient de décharge / mesure de débit / passe à fentes vert...

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Section: 3mentioning

confidence: 99%

Villemonte's approach: a general method for modeling uniform and non-uniform performance in stepped fishways

Fuentes‐Pérez

García‐Vega

Sanz‐Ronda

et al. 2017

Knowl. Manag. Aquat. Ecosyst.

View full text Add to dashboard Cite

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“…Bathurst (1985) was left to conclude that the complicated nature of the flow resistance processes, coupled with the lack of available data, currently prevent the development of a satisfactory practical method for predicting flow resistance in steep mountain rivers. More recently, Pagliara & Chiavaccini (2006) and Pagliara, Das, and Carnacina (2008) investigated flow resistance in steep chutes with large-scale roughness that comprised protruding boulders in some cases. Bed slope, relative submergence and boulder arrangement were systematically altered and a logarithmic expression for f was obtained and was shown to fit the available experimental data well.…”

Section: Introductionmentioning

confidence: 99%

Free surface flow over square bars at intermediate relative submergence

McSherry

Chua

Stoesser

et al. 2018

Journal of Hydraulic Research

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Results from large-eddy simulations and complementary flume experiments of turbulent open channel flows over bed-mounted square bars at intermediate submergence are presented. Scenarios with two bar spacings, corresponding to transitional and k-type roughness, and three flow rates, are investigated. Good agreement is observed between the simulations and the experiments in terms of mean free surface elevations and mean streamwise velocities. Contours of simulated time-averaged streamwise, streamfunction and turbulent kinetic energy are presented and these reveal the effect of the roughness geometry on the water surface response. The analysis of the vertical distribution of the streamwise velocity shows that in the lowest submergence cases no logarithmic layer is present, whereas in the higher submergence cases some evidence of such a layer is observed. For several of the flows moderate to significant water surface deformations are observed, including weak and/or undular hydraulic jumps which affect significantly to the overall streamwise momentum balance. Reynolds shear stress, form-induced stress and form drag are analysed with reference to the momentum balance to assess their contributions to the total hydraulic resistance of these flows. The results show that form-induced stresses are dominant at the water surface and can contribute significantly to the overall drag, but the total resistance in all cases is dominated by form drag due to the presence of the bars.

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“…The formulation generally used is the Manning-Strickler formula, which allows a simple calibration of the hydrodynamic models. The limitations of this formulation have been exposed in cases where the sizes of the roughness elements are similar to the water depth (strong confinement), torrential flow [1], vegetated beds [2,3], unsteady flow, or hyperconcentrated flow [4]. To mitigate these problems, many studies have sought to describe experimentally how friction changes with water depth, slope, or Froude number.…”

Section: Introductionmentioning

confidence: 99%

A Semi-Analytical Model for the Hydraulic Resistance Due to Macro-Roughnesses of Varying Shapes and Densities

Cassan

Roux

Garambois

2017

Water

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A friction model resulting from investigations into macro-roughness elements in fishways has been compared with a broad range of studies in the literature under very different bed configurations. In the context of flood modelling or aquatic habitats, the aim of the study is to show that the formulation is applicable to both emergent or submerged obstacles with either low or high obstacle concentrations. In the emergent case, the model takes into account free surface variations at large Froude numbers. In the submerged case, a vegetation model based on the double-averaging concept is used with a specific turbulence closure model. Calculation of the flow in the roughness elements gives the total hydraulic resistance uniquely as a function of the obstacles' drag coefficient. The results show that the model is highly robust for all the rough beds tested. The averaged accuracy of the model is about 20% for the discharge calculation. In particular, we obtain the known values for the limiting cases of low confinement, as in the case of sandy beds.

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Flow Resistance of Rock Chutes with Protruding Boulders

Cited by 69 publications

References 22 publications

Villemonte's approach: a general method for modeling uniform and non-uniform performance in stepped fishways

Villemonte's approach: a general method for modeling uniform and non-uniform performance in stepped fishways

Free surface flow over square bars at intermediate relative submergence

A Semi-Analytical Model for the Hydraulic Resistance Due to Macro-Roughnesses of Varying Shapes and Densities

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