The turbulent flow in natural rough-bed watercourses is a rather complex phenomenon, still poorly investigated. The majority of the existing works on this subject is of experimental nature, while the numerical ones are mostly related to artificially and regularly-roughened beds. In the present work a numerical investigation is carried out, in which the fully turbulent flow in an open channel is simulated, where the channel bottom is constituted by natural-pebble layers. In the numerical simulations, the Large Eddy Simulation (LES) approach is used, in conjunction with the Wall-Adapting Local Eddy viscosity (WALE) Sub-Grid Scale (SGS) closure model at Reynolds number 46,500 and Froude number 0.186. The Finite-Volume discretized governing equations are solved numerically by means of the InterFOAM solver, embedded in the OpenFOAM C++ digital library. In order to take into account the free-surface dynamics, the Volume of Fluid (VoF) method has been used. The results of the simulations are compared with those obtained in a companion experiment, mainly in terms of turbulence statistics of different order, obtaining a rather good agreement.

Numerical Investigation of Natural Rough-Bed Flow

ALFONSI G.;FERRARO D.;LAURIA A.
;
GAUDIO R.
2020

Abstract

The turbulent flow in natural rough-bed watercourses is a rather complex phenomenon, still poorly investigated. The majority of the existing works on this subject is of experimental nature, while the numerical ones are mostly related to artificially and regularly-roughened beds. In the present work a numerical investigation is carried out, in which the fully turbulent flow in an open channel is simulated, where the channel bottom is constituted by natural-pebble layers. In the numerical simulations, the Large Eddy Simulation (LES) approach is used, in conjunction with the Wall-Adapting Local Eddy viscosity (WALE) Sub-Grid Scale (SGS) closure model at Reynolds number 46,500 and Froude number 0.186. The Finite-Volume discretized governing equations are solved numerically by means of the InterFOAM solver, embedded in the OpenFOAM C++ digital library. In order to take into account the free-surface dynamics, the Volume of Fluid (VoF) method has been used. The results of the simulations are compared with those obtained in a companion experiment, mainly in terms of turbulence statistics of different order, obtaining a rather good agreement.
978-3-030-40616-5
Pebble bed flow, Large Eddy Simulation, Volume of Fluid
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/298544
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