(2021). Hydraulic engineering of dams. Journal of Hydraulic Research. Ahead of Print.

(2021). Correction. Journal of Hydraulic Research. Ahead of Print.

Separation in overflow spillways may occur when the hydraulic head is considerably greater than the design head. In this study, results obtained in a separation that occurred in a physical model were used for a numerical analysis of the phenomenon. A three-dimensional computational programme was used and the results using none or one of six different turbulence models were compared to the experiment

In experiments with vegetated flows, natural plants are often represented by artificial surrogates, which eliminate effects of plants physiology to easy fit the experimental set-ups. Using surrogates of flexible aquatic plants, the buoyancy and rigidity are supposed to match those in tissues of the natural plants. This paper introduces a new technique for manufacturing composite surrogates from silicon

This paper presents an experimental study of angled fish-friendly bar racks with horizontal bars, using a physical model in an open channel. Head losses are investigated for two bar shapes, three ratios between bar spacing and bar thickness and four angles of orientation of the racks. The Froude and bar-Reynolds numbers were respectively 0.275 and 3600. The head loss coefficients decrease as the blockage

Following on from a theoretical solution to the Kelvin–Helmholtz (KH) instability under submerged canopy-oscillatory flow environments a relationship between the incoming free surface wave frequency and KH frequency was developed. The KH frequencies ( fKH) are higher than those from the incoming wave expressed by fKH ≈[2.83,5.02]fw. In addition, the analytical expression, along with the energy spectra

The vortex-induced vibration of the aqueduct girder may excite the parametric sloshing of the contained water which will have substantial impacts on the normal running and structural safety of the aqueduct bridge. This paper first conducts a wind-tunnel experiment to investigate the auto-parametric sloshing caused by wind vortex-induced vibration for an elastically-hung rectangular aqueduct with contained

In this paper, a large-eddy simulation study of turbulent free surface flow over a natural rough bed is presented. A three-dimensional multiphase flow model is employed to study the roughness effects on the turbulence properties and free surface dynamics. The governing equations have been discretized using the finite volume method, with the Cartesian cut-cell method being implemented to deal with the

Semi-permeable sediment traps are designed to retain sediment during large floods and enable sediment transport continuity during ordinary floods by combining two barriers with a guiding channel. During floods, not only sediment but also large wood (LW) can be transported, that may block the inclined bar screen (mechanical barrier) and inhibit sediment transport. The design of the inclined bar screen

The current research focuses on the analysis of different dynamic effects of an air pocket located at mid-pipe length on transient pressures based on experimental data. Different flow rates and air pocket volumes are analysed. Several features are identified in the pressure-head signal associated with the air pocket: initial pressure drop, higher maximum overpressure peaks, increased pressure wave

Previous research has shown that the inflow conditions upstream of hydraulic jumps can affect flow aeration, bed pressures and turbulence. However, studies of the effects of inflow conditions on free-surface properties have not been conclusive and have lacked a comparison of partially and fully developed inflow conditions. Detailed measurements of the free-surface features in fully aerated hydraulic

ABSTRACT Cavitation erosion is a fundamental concern in many fields of engineering, e.g. the flow separation zone in high speed flow and the blade area of hydraulic machinery. However, the influence of the physical characteristics of the environmental medium in these engineering facilities on cavitation erosion is still unclear. In this paper, we adopted underwater low-voltage discharge technology

This study presents experimental investigations of entrainment events of a single sediment particle resting in a small pocket on a smooth bed in an open channel flow. The data were acquired with a tomographic particle tracking velocimetry system. The shake the box algorithm, a spatially high resolved Lagrangian tracking method, was applied to determine time-resolved and three-dimensional flow velocities

In this study, a two-dimensional shallow-water-equation numerical model is developed for simulating free surface water flows with internal moving wet/dry front boundaries. It is based on the Eulerian aspect and meshless approach. The predictor-corrector process is used for the time marching. The spatial derivatives of physical quantities are computed using the local polynomial approximation with the

ABSTRACT An experimental analysis of the dynamics of avalanches for different stages of development and turbulent flow conditions is introduced. Experiments were conducted in a laboratory flume using clear-water conditions and a video camera placed within an acrylic cylinder. The results of a proper orthogonal decomposition of the pre-processed image sequences highlighted the existence of two types

To reduce local scour around bridge piers, a mitigation measure requiring a submerged triangular flow diversion structure is proposed. Different dimensions, locations, and submergence ratios were examined experimentally. Using Taguchi’s method to minimize the number of alternative tests, 27 alternative tests were undertaken to ascertain the optimum size and location for the structure. Compared to the

ABSTRACT Aquatic vegetation is an important component of coastal and riverine environments and plays a significant role in shaping their evolution. The extent and nature of eco-hydraulic interaction depends upon the geometric and biophysical properties of the vegetation which affect the drag force and vegetation reconfiguration. Such vegetation properties commonly vary along each stem. However, this

Erosion of sediments is of crucial significance to morphologic evolution, management of water quality and aquatic ecosystems. However, the prediction of the pickup rate of non-cohesive sediments is a challenging topic because of the complex interaction between the bed and the flow. This study reports the experimental results of the pickup rate of non-cohesive sediments in uniform flows. Six groups

One of the most used 1D tools to model collection systems is the Storm Water Management Model (SWMM). Solving the full form of the Saint Venant equations, this model represents typical unsteady flow conditions in sewer systems. However, it may be insufficient to address fast transient flow conditions that can be present during extreme events or unscheduled operational conditions. SWMM version 5.1.013

A series of lock-release experiments are carried out to investigate the hydrodynamics of weakly and strongly stratified two-layer gravity currents (GC) on a flat bottom. A particle image velocimetry (PIV) system combined with an optical method is used to obtain the mixing process, front velocity, and velocity profiles of the two-layer GCs, focusing on the effect of the initial height ratio and lock

ABSTRACT In the proposed work, a numerical model of the water flow during dam breakthrough using the volume of fluid (VOF) method is constructed. The mathematical model consists of a system of Navier–Stokes equations, and also includes equations for the phase and motion of particles. For the simulation, the SST k−ω turbulent model was used. To solve the system of equations, the PISO algorithm was used

The turbulent plunging jet of a nearly incompressible fluid into a stagnant fluid is of great importance in many practical applications, especially for the engineering of hydropower. As an example, the dynamic load exerted by the impact of turbulent high-velocity jets into a pool must be estimated to evaluate the potential destabilization of a rock bed or dam’s structure. Modelling plunging jets in

This paper presents both experimental measurements and three-dimensional (3D) numerical simulations of turbulent flow in open channels with simulated partial ice-covers. The experiments were conducted with a particle image velocimetry system while the simulations were performed with five eddy-viscosity and second-moment closure turbulence models. Four coverage ratios based on the channel width were

A well-balanced and positivity-preserving meshless method based on smoothed particle hydrodynamics (SPH) is developed to simulate one-dimensional (1D) and two-dimensional (2D) shallow water (SW) flows in open channels with irregular geometries. A new form of the characteristic equations that govern the water-surface level and water velocity is introduced to specify the numerical inflow/outflow boundary

(2021). Comparison between hydrostatic and total pressure simulations of dam-break flows By LEONARDO R. MONTEIRO, LUÍSA V. LUCCHESE and EDITH B. C. SCHETTINI, J. Hydraulic Res. 58(5), 725–737. Journal of Hydraulic Research: Vol. 59, No. 2, pp. 351-354.

(2021). Closure to “Comparison between hydrostatic and total pressure simulations of dam-break flows” by LEONARDO R. MONTEIRO, LUÍSA V. LUCCHESE and EDITH B. C. SCHETTINI, J. Hydraulic Res., 58(5), 725–737. https://doi.org/10.1080/00221686.2019.167150. Journal of Hydraulic Research: Vol. 59, No. 2, pp. 354-354.

(2021). Correction. Journal of Hydraulic Research: Vol. 59, No. 2, pp. ciii-ciii.

Over the last two decades, interest in the free-surface behaviour of gravity-driven shallow turbulent flows has increased considerably. It is believed that observation of free-surface behaviour can provide useful information about the hydrodynamic characteristics of the flow and enable remote retrieval of these characteristics to non-invasively and rapidly monitor river flows. At the current state

Hydraulic structures are man-made waterworks interacting with the rainfall run-off to store and convey water, or mitigate the impact of run-off. Current approaches in hydraulic structure design tend to be conservative, not much differing from ancient designs. Modern structures are often designed based upon simplistic concepts to optimize their performances. However, today’s hydraulic engineers must

(2021). A Lagrangian drifter for surveys of water surface roughness in streams By CHRISTIAN NOSS, KAAN KOCA, PEGGY ZINKE, PIERRE-YVES HENRY, CHRISTY USHANTH NAVARATNAM, JOCHEN ABERLE and ANDREAS LORKE, J. Hydraulic Res. 58(3), 471–488. https://doi.org/10.1080/00221686.2019.1623930. Journal of Hydraulic Research: Vol. 59, No. 1, pp. 176-178.

(2021). Closure to “A Lagrangian drifter for surveys of water surface roughness in streams” by CHRISTIAN NOSS, KAAN KOCA, PEGGY ZINKE, PIERRE-YVES HENRY, CHRISTY USHANTH NAVARATNAM, JOCHEN ABERLE and ANDREAS LORKE, J. Hydraulic Res. Journal of Hydraulic Research: Vol. 59, No. 1, pp. 178-179.

Experiments are conducted in a Ø600 mm tank to analyse the 3D motion of buoyant particles in the free-surface vortex flow. The experiments revealed two stages in the particle motion: stage 1 is the helical motion along the vortex air core and stage 2 is the axial motion inside the vortex core. The stage 1 motion is sensitive to the particle’s initial conditions by showing a chaotic behaviour and quantified

Spatially varied flows with increasing discharge can be encountered in several hydraulic systems. The analysis of water surface profiles in such flow conditions is useful for the verification and design of these systems. In this paper, a comprehensive analysis of the possible flow profiles in non-prismatic trapezoidal channels is performed using the method of singular points, by taking into account

For design and management of large scale tunnels, it is important to model the transitions between pressurized and free-surface flows inside them. The pressurized and free-surface flow regimes are separated by a discontinuity with different wave speeds on two sides, which makes efficient and accurate simulations still challenging. A robust and conservative space-time adaptive mesh refinement (AMR)

A multi-phase smoothed particle hydrodynamics (SPH) formulation in combination with a granular rheological model is applied to simulate the 2007 Chehalis Lake landslide and the subsequent tsunami. The model is implemented within the open-source 3D code GPUSPH. The lake geometry is built using the British Colombia Hydro (BCH) topography and bathymetry surveys, and the landslide initial geometry is reconstructed

ABSTRACT The effects of the variation of the viscoelastic pipe material properties on the transient pressure wave propagation are investigated through laboratory and numerical tests. The used experimental set-up consists of a series of a high-density polyethylene (HDPE) pipe with an oriented polyvinyl chloride (PVC-O) pipe. A pulse and a step pressure wave are introduced in the system using an automatically

This paper presents a new sub-grid flood inundation model aimed at high computational performance. The model solves the two-dimensional shallow water equations (SWE) by a Godunov-type finite volume (FV) method that uses two nested meshes. Runtime computations are performed at a coarse computational mesh, while a fine mesh is used to incorporate fine resolution information into the solution at pre-processing

Various transient test-based techniques have been developed for detecting leaks in pipeline systems, and most of these depend on a signal that is reflected by the leak. In field pipes, this signal is easily disturbed by high frequency noise, which can prevent detection. This paper presents a leak detection method using transient pressure damping by energy dissipation from the leak, which is minimally

ABSTRACT Two computational fluid dynamics models were developed to analyse the internal fluid mechanics of an Archimedes screw’s buckets. The models were evaluated against laboratory-scale experimental data, which suggested that they were acceptably accurate. Results of power-generating torque, internal fluid velocities, wall shear stress, and leakage flow rates were all explored with respect to changing

Both the apparent bedload velocity and the backscattering strength measured by acoustic Doppler current profilers could assist bedload assessment in the field. To test this hypothesis, two ADCPs working at three frequencies (3 MHz and 1 MHz, M9; 2 MHz, StreamPro) were deployed simultaneously to measure seven different bedload transport conditions in a laboratory flume. The bedload transport was monitored

This work presents a numerical study of a skimming flow regime in a stepped spillway structure, which is a complex two-phase flow with self-aeration phenomenon. The numerical models employed consist in a hybrid approach capable of switching between interface resolving and interface modelling closures on a local level, and a state-of-the-art volume-of-fluid (VOF) method. A new switch criterion for the

ABSTRACT Measuring flow depths in free-surface turbulent flows can be challenging due to their fast dynamics and the presence of aeration. This study analyses the suitability of a low-cost sensor, the Intel® RealSense™ D435 RGB-D camera, for characterization of a highly aerated case study: the hydraulic jump. As with all instrumentation, special care must be taken to ensure accurate measurements. In

Conventional rectangular side weirs installed along prismatic open-channels may have low efficiency. One practical way to overcome this problem may be to insert the weir in the oblique side of a converging channel. In this paper, the performance of oblique straight side weirs or two-segment single-cranked side weirs inserted in rectangular converging channels are analysed through 3D computational fluid

ABSTRACT Hydraulic characteristics of swirling flow at shaft spillways with an innovative inlet, namely the marguerite-shaped inlet, is investigated based on model experimentation. Detailed measurements of head–discharge relationship, flow regimes, water free-surface profiles, flow circulation, discharge coefficient and threshold and critical submergence depths were performed for shaft spillways with

Conventional rectangular side weirs installed along prismatic open-channels may have low efficiency. One practical way to overcome this problem may be to insert the weir in the oblique side of a converging channel. In this paper, the performance of oblique straight side weirs or two-segment single-cranked side weirs inserted in rectangular converging channels are analysed through 3D computational fluid

The present laboratory study used particle image velocimetry (PIV) to measure transitional flow regimes during the jet-flipping process, which is cyclical in the scour hole downstream of a sluice gate with an apron. The transitional vortical structures during jet flipping (both upward and downward) are clearly captured and discussed. Various vortices are formed in the scour hole by two pairs of component

Various empirical equations for mean bed and wall shear stresses have been proposed for smooth rectangular open channels. Considering that the distribution of bed shear and wall shear stresses is affected by the cross-sectional shape, the gravity force based on the flow depth used to non-dimensionalize shear stresses in previous studies is modified to a parameter that includes the width and wetted-perimeter

ABSTRACT Existing pipe-filling models have primarily considered steady friction alone, tending to underestimate pressure attenuation. Various popular unsteady friction models are considered here to simulate pressures within a rapidly filling vertical pipe. Numerical predictions are compared to each other and to experimental results. The models considering unsteady friction better reproduce measured

This article highlights the theoretical and experimental research of Leopold Escande, conducted in hydraulic engineering. He is considered one of the great European leaders in this field from 1930 ...

The processes of sediment transport in high flow intensity are studied through numerical simulation using a coupled CFD (computational fluid dynamics)-DPM (discrete particle method) model with a focus on discussing the co-existence problem of bed load and suspended load and the corresponding sediment concentration distribution. It is shown that for the sediment-laden flows, the components of turbulence

Reflections of the surface waves in hydraulic wave flumes could affect the performance of the common piston, hinged and plunger type wavemakers. This paper proposes a new wavemaker to produce surface waves where the possible reflections are barely able to affect its performance. The proposed wavemaker includes an oscillating paddle at the bottom of the flume where the produced upward flow induces travelling

The processes of sediment transport in high flow intensity are studied through numerical simulation using a coupled CFD (computational fluid dynamics)-DPM (discrete particle method) model with a focus on discussing the co-existence problem of bed load and suspended load and the corresponding sediment concentration distribution. It is shown that for the sediment-laden flows, the components of turbulence

Reflections of the surface waves in hydraulic wave flumes could affect the performance of the common piston, hinged and plunger type wavemakers. This paper proposes a new wavemaker to produce surface waves where the possible reflections are barely able to affect its performance. The proposed wavemaker includes an oscillating paddle at the bottom of the flume where the produced upward flow induces travelling

ABSTRACT Transverse solute mixing across a vegetation generated horizontal shear layer was quantified using laser induced fluorometry techniques for artificial and real vegetation. A two-dimensional finite difference model (FDM) was developed to describe transverse concentration profiles for flows containing transverse variations in velocity and transverse dispersion, from a steady solute input. The

Accurate prediction of the discharge through radial gates is difficult. Existing calibration methods typically provide sufficient accuracy for free flows and submerged flows with jet Froude number at vena contracta larger than 1.7. However, their predictions are poor for submerged flows with jet Froude number less than 1.7. Based on the analysis of experimental data collected by the US Bureau of Reclamation

Accurate prediction of the discharge through radial gates is difficult. Existing calibration methods typically provide sufficient accuracy for free flows and submerged flows with jet Froude number at vena contracta larger than 1.7. However, their predictions are poor for submerged flows with jet Froude number less than 1.7. Based on the analysis of experimental data collected by the US Bureau of Reclamation

ABSTRACT Transverse solute mixing across a vegetation generated horizontal shear layer was quantified using laser induced fluorometry techniques for artificial and real vegetation. A two-dimensional finite difference model (FDM) was developed to describe transverse concentration profiles for flows containing transverse variations in velocity and transverse dispersion, from a steady solute input. The

A numerically-based approach is used to obtain a size selection formula for the riprap stone part of the apron used to protect wing-wall abutments against erosion. Several series of simulations with a given mean riprap diameter are conducted to estimate the maximum bed shear stress over the riprap apron and then the maximum (critical) Froude number at which riprap stones will resist shear failure by

A new airborne river surface flow measurement technique is presented, called Airborne Feature Matching Velocimetry (AFMV). It uses matchings of characteristic image features for orthorectification and velocimetry. Riparian matching points with an arbitrarily chosen base image serve to find individual projective transformation matrices to stabilize airborne video recordings. Transformed matching points’

(2020). Statistical analysis methods for transient flows – the dambreak case. Journal of Hydraulic Research: Vol. 58, No. 6, pp. 1004-1005.