This paper proposes a model for predicting the longitudinal profiles of streamwise velocities in an open channel with a model patch of vegetation. The governing equation was derived from the momentum equation and flow continuity equation. The model can estimate the longitudinal profiles of velocities both inside and outside a vegetation patch. Laboratory experiments indicate that the longitudinal profiles

In this work, a summary of Leonardo da Vinci’s contribution in the field of fluid mechanics is reported. Some theoretical laws or fluid flows analyzed or drawn by Leonardo are highlighted, such as vortices, flow fields with obstacles, the continuity law, waves, velocity profiles in open channels, as well as some ingenious contributions in the field of hydraulic constructions and machines.

The results of an experimental study on the turbulence characteristics in flow over and downstream of an isolated bedform are presented. The vertical profiles of time-averaged streamwise velocity, Reynolds stresses and turbulent kinetic energy (TKE) fluxes at different horizontal locations over and downstream of a bedform are shown to demonstrate their variations. The experimental results signify a

Transport of air pollutants emitted from urban valleys can be strongly restricted by interactions between static and dynamic factors including topographic forcing, low-level atmospheric stability related to temperature inversions, and urban heat island-induced circulations. Interplay between these processes has a complex and dynamic nature, and is determinant for the evolution of different ventilation

In plunging jets and at hydraulic jumps, large amounts of air bubbles are entrained at the impingement of the liquid jet into the receiving body. Air is entrapped and advected into a turbulent shear layer with strong interactions between the air bubble advection process and momentum shear flow. In this new physical study, air–water flow measurements were systematically repeated with identical inflow

A compression wave is an unsteady rapidly-varied open channel flow motion, characterised by an increase in water depth. A detailed investigation was conducted in a prismatic asymmetrical channel, to better understand the physical processes observed in tidal/tsunami-bore affected estuaries with irregular topography. The prismatic channel was equipped with a 1 V:5H transverse slope across the full channel

Modern turbulence models allow for detailed numerical solutions, involving millions of data points and numerous degrees of freedom; these solutions have the potential to provide notable insights into the flows past hydraulic structures. In this paper, we present new analyses of a Detached-eddy simulation of the flow past stepped spillways in three dimensions, in order to investigate the coherent structures

The present paper analyses the advantages and limitations of using numerical modelling to simulate hydraulic jumps at high Froude numbers. Two hydraulic jumps of the same Froude number (7.5) but different Reynolds numbers were simulated using Improved Delayed Detached Eddy Simulation. The free surface was captured using the Volume of Fluid multiphase model with a High-Resolution Interface-Capturing

Near-bed flows in rough-bed open-channels are of relevance to river engineering, freshwater ecology and hydraulic design. Detailed measurements of near-bed flow velocity and turbulence distributions are rarely available. This paper aims to improve our understanding of near-bed flow characteristics. We performed experiments of turbulent open-channel flow over roughness elements, and made fine-scale

Wood is recognized as a key element of river ecosystem for a large number of positive feedbacks with biotic and abiotic components, both when it is present as large wood deposit or as live vegetation on the riparian zone. Despite the positive impacts of wood, when considering the high flow events, the presence of woody riparian vegetation within the channel can increase the potential risk related to

A numerical procedure is proposed to estimate the velocity distribution in open channel flow, for engineering applications. A method based on the mixing length model and sub-division of the wetted surface, is modified to easily integrate a lateral distribution of roughness. Several friction models for vegetated or rough flows can be added, two of which have been tested. The numerical procedure was

The results of large-eddy simulations of flow and transient solute transport over a backward facing step and through a 180° bend are presented. The simulations are validated successfully in terms of hydrodynamics and tracer transport with experimental velocity data and measured residence time distribution curves confirming the accuracy of the method. The hydrodynamics are characterised by flow separation

This paper discusses the need for critically evaluating regional-scale (~200-2000 km) three-dimensional numerical photochemical air quality modeling systems to establish a model's credibility in simulating the spatio-temporal features embedded in the observations. Because of limitations of currently used approaches for evaluating regional air quality models, a framework for model evaluation is introduced

We investigated temporal variations in turbidity in Base Mine Lake, an oil sands pit lake, located in northeast Alberta, Canada. The lake has a surface area of 7.8 km2, is 9 m deep, and exhibits seasonal thermal stratification similar to that of natural dimictic lakes. Water turbidity was measured continuously throughout the year with moored sensors, supplemented with turbidity profiles and bottle

Bridges with and without piers are prone to large wood (LW) accumulations during floods, possibly resulting in an upstream backwater rise, local scour, or destabilization of the structure. To reduce the flood hazard, measures are required that decrease the accumulation probability p of LW. This paper presents a literature review on existing measures to reduce p at bridges. In addition, a series of

The performance of a rake for large wood retention has been analysed in clean water and for the case of a slit check dam. An experimental investigation was conducted in a steep rectangular flume, by employing regular cylinders at different rates and rake geometry. The effects of the inclination and distance of the rake from the check dam have been analysed in terms of the trapping efficiency and backwater

The paper addresses the influence of intense sediment transport (bed load and debris flow) on the efficiency of the structures aimed at the interception of wood logs. In the literature different devices designed to intercept woods are proposed: steel barriers, net barriers, check dam with steel bars positioned in the opening. In this paper we firstly define some fundamental dimensionless parameter

The presence of floaters should be taken into account when dealing with hydraulic analyses, e.g. when boats are moored along the river banks or large wood is expected to be conveyed by the river flow during floods. Many approaches have been proposed so far in order to consider the effects of floaters upon the flow features. Usually, they rely on the numerical resolution of the governing equation for

Predicting the motion of driftwood around hydraulic structures such as bridge piers and spur dikes is important. We propose a numerical model for simulating driftwood motion that is based on coupling an Eulerian-type three-dimensional flow model and a Lagrangian-type two-dimensional driftwood model. Laboratory tests were carried out on the driftwood motion in a curved channel and around obstacles to

The blockage of weirs or bridges by in-stream wood can reduce the flood discharge capacity, leading to hazardous situations. To assess the related risk, blocking probabilities quantifications are needed. However, large wood has a random behaviour and it is challenging to accurately evaluate the blockage process and the influence of different large wood or hydraulic parameters properly. Investigations

Turbulent flow through and over vegetation continues to draw significant research attention given its relevance to a plethora of applications in earth and environmental science. Canopy flows are characterized by three-dimensional coherent vortical motions not directly accessible from single-point measurements, which pose a challenge to formalizing links between vegetation structure and turbulent motion

The Eulerian–Lagrangian model ORSA2D_WT is employed for the simulation of uncongested wood transport, with reference to a field experiment that studied the motion of regular and unbranched cylindrical wooden samples. The model calculates the entrainment, transport and deposition of large wood elements by computing the hydrodynamic forces exerted by the flow. The experimental log positions and displacements

A series of small- and large-scale experiments and numerical simulations were carried out to produce datasets for maximum scour depth at the base of longitudinal structures. The small-scale experimental datasets were employed to develop an empirical relationship for predicting maximum local scour depth. The measured datasets for scour patterns and depths were used to validate the accuracy of our morphodynamics

Computational modeling of open-channel flows is usually carried out using the rigid-lid (RL) assumption to prescribe the water surface. Such an approach deems more appropriate for sub-critical flow regimes with Froude number ≪ 1. When the Froude number is locally high, e.g. flows around hydraulic structures, the free-surface fluctuations affect the induced hydrodynamics. Indeed, prior investigations

A culvert is a covered channel designed to pass water through an embankment. The recognition of the adverse ecological impacts of culverts on upstream fish passage is driving the development of new culvert design guidelines, with a focus on small-bodied fish species seeking low velocity zones to minimise energy expenditure. Herein a hybrid modelling technique was applied, combining physical modelling

In recent decades, the advancement of knowledge on the hydraulics of labyrinth weirs has resulted mainly from physical modeling. In this study, numerical simulations of free-flow and submerged labyrinth weirs were conducted for a large sidewall angle, using commercially available computational fluid dynamics software, for three different turbulence models. These simulations were compared with experimental

Wood transport during high flow events is here treated as an advective–diffusive phenomenon. A theoretical definition of the governing equation is first provided, highlighting the dependence of floating wood diffusion on the adoption of adequate diffusion coefficients. To estimate these coefficients, an experimental investigation on large wood debris was carried out in a channel presenting a weakly

The present paper, places emphasis on the vorticity induced by wave breaking, which greatly contributes to sediments pick up and suspension as well as to air–water exchange at the wave interface, thus deserving a thorough study. A weakly-compressible smoothed particle (WCSPH) model, coupled with a two-equation model for turbulent stresses, has been employed for this scope. A careful calibration of

Laboratory experiments are conducted to examine a descending plume in a rotating two-layer stratified ambient fluid such that the plume at the interface has moderate to large Rossby number. While the source fluid is more dense than the lower layer, the experiments are designed so that the mean density of the plume fluid impinging upon the interface is less than the lower layer density, as represented

Hunter Rouse was the father of the Fluid Mechanics of Open Channel Flow. In this review article the fundamental advances on the non-hydrostatic modeling of shallow open channel flow over topography, since the publication of his 1938 book, are discussed. Flows over uneven topography, like at open channel controls, occurs in a short length, thus rendering ideal fluid flow theory an adequate mathematical

To disseminate the role of the eddy motions on the anisotropic states of the Reynolds stress tensor (\(\varvec{B}\)), we devise a novel methodology based on the quadrant analysis, where the distributions of the invariants of \(\varvec{B}\) are studied on a \(u^{\prime }\)–\(w^{\prime }\) quadrant plane, with \(u^{\prime }\) and \(w^{\prime }\) being the turbulent fluctuations in the streamwise and

During the last decades, concerns regarding the ecological impact of standard culverts have led to some design evolution. The installation of baffles along the culvert barrel yields smaller velocities and larger water depths in the barrel, potentially more suitable for upstream fish passage, albeit with a decrease in discharge capacity. Small triangular corner baffles were proposed to facilitate the

Eco-friendly low-head river restoration structures such as block ramps are of paramount importance with regard to the control of sediment grade in rivers, particularly in the mountains. They also help in the stabilization of river bed and prevent damages due to excessive downstream erosion by dissipating flow energy. Although the hydraulic characteristics of block ramps in straight channels have been