Search results for "vegetated channel"
showing 3 items of 3 documents
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…
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…
Comment on "Measuring the flow resistance of submerged grass"
2004
In this short note, the experimental data of Wilson and Horritt (2002.Hydrological Processes16: 2589–2598), jointlywith the measurements by Kouwenet al. (1969.Journal of Irrigation and Drainage Division, ASCE95: 329–342)and by Raffaelliet al. (2002 InProceedings XXVIII Convegno di Idraulica e Costruzioni Idrauliche, Cosenza, Italy;223–230), arefirstly used to test Kouwen’s approach. All experimental data are then used to calibrate aflow resistanceequation that was theoretically deduced by dimensional analysis and self-similarity theory