Search results for " Flexible vegetation"

showing 3 items of 3 documents

Experimental investigation on dispersion mechanisms in rigid and flexible vegetated beds

2018

Vegetation in channels strongly affects flow structure and turbulence, with consequences on the hydrological storage of nutrients and chemical tracers, the shelter of stream biota as well as the trapping or transport of sediments. At the same time, all these phenomena are inevitably subjected to alteration of hydrological conditions in fluvial systems due to climate change. The present study intends to provide a thorough investigation into the processes of transport and dispersion induced by flow turbulence within the vegetation structure. Specifically, velocity measurements in vegetated channels were intensively conducted and analyzed in the case of both flexible submerged and rigid emerge…

HydrologyTurbulence0208 environmental biotechnologyFlow (psychology)Rigid vegetationClimate changeSoil scienceBiotaAdvective transport02 engineering and technologyVegetationRigid vegetation flexible vegetation turbulent length dispersion advective transportDispersionPhysics::Geophysics020801 environmental engineeringSettore ICAR/01 - IdraulicaPhysics::Fluid DynamicsCurrent (stream)Environmental scienceSpatial variabilityDispersion (water waves)Flexible vegetationTurbulent lengthWater Science and Technology
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Turbulent mixing and dispersion mechanisms over flexible and dense vegetation

2019

The present study investigates flow turbulence and dispersion processes in the presence of flexible and dense vegetation on the bed. The turbulent dispersion coefficients and the terms of the turbulent kinetic energy equation are determined by using data collected in a straight laboratory channel with living vegetation on the bed. Results show that the turbulent integral lengths assume an order of magnitude comparable to the stems’ characteristic dimension independently by the direction and the turbulence assumes an isotropic behavior. The coefficients of dispersion have a trend similar to that of the turbulent lengths and assume low values in the longitudinal, transversal and vertical dire…

PhysicsTurbulent diffusion010504 meteorology & atmospheric sciencesTurbulenceIsotropyMechanicsDissipation010502 geochemistry & geophysics01 natural sciencesSettore ICAR/01 - IdraulicaNonlinear Sciences::Chaotic DynamicsPhysics::Fluid DynamicsGeophysicsFree surfacePhysics::Space PhysicsTurbulence kinetic energyWake turbulenceVegetated channels Flexible vegetation Turbulence DispersionOrder of magnitude0105 earth and related environmental sciencesActa Geophysica
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Analysing longitudinal turbulence intensity in vegetated channels

2007

Vegetation altering hydrodynamic conditions of an open channel flow controls the exchanges of sediment, nutrients and contaminants. In this paper the turbulence structure of open-channel flow over a flexible grass vegetation is investigated. Velocity measurements were carried out, in a rectangular flume, using a 2D-ADV (Acoustic Doppler Velocimeter) for different values of stem concentration, water discharge, and bed slope. The experimental results showed that: 1) the maximum value of the longitudinal turbulence intensity occurs at a water depth close to the bent vegetation height; 2) the turbulence intensity damps for increasing values of the stem concentration; 3) above the vegetation hei…

TurbulenceMechanical EngineeringMaximum flow problemFlow (psychology)lcsh:SBioengineeringAtmospheric scienceslcsh:S1-972Industrial and Manufacturing EngineeringOpen-channel flowopen-channel turbulence vegetationlcsh:AgriculturePhysics::Fluid DynamicsFlumeVegetated channels Flexible vegetation Acoustic Doppler Velocimeter Turbulence intensity Relative turbulence intensity.Turbulence kinetic energymedicineEnvironmental scienceAcoustic Doppler velocimetrylcsh:Agriculture (General)medicine.symptomVegetation (pathology)
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