The present study investigates flow turbulence and dispersion processes in the presence of flexible and dense vegetation onthe bed. The turbulent dispersion coefficients and the terms of the turbulent kinetic energy equation are determined by usingdata collected in a straight laboratory channel with living vegetation on the bed. Results show that the turbulent integrallengths assume an order of magnitude comparable to the stems’ characteristic dimension independently by the directionand the turbulence assumes an isotropic behavior. The coefficients of dispersion have a trend similar to that of the turbulentlengths and assume low values in the longitudinal, transversal and vertical directions. Results also show that, in the mixinglayer, the shear and wake turbulence production terms balance the dissipation; the turbulent diffusion term also assumes lowvalues and its sign varies along the vertical indicating a transport of turbulent energy both from the vegetation to the freesurface and from the free surface to vegetation.
|Numero di pagine||10|
|Stato di pubblicazione||Published - 2019|
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