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The Lattice Boltzmann Method (LBM) is a mesoscopic method founded on the kinetic theoryof Boltzmann and has been proven to describe successfully flows of hydraulic interest such asturbulent, multicomponent and multiphase flows. The main advantage of the LBM, comparedto more traditional methods of the Computational Fluid Dynamics, are: the simplicity of theset of explicit algebraic equations forming the computational algorithm, the ease ofdescription of complex boundaries and the proneness of the LBM to provide unprecedentedparallel scalability on a large number of architectures. Thus, the computational resourcesavailable nowadays make the employment of 3D models feasible to study large-scaleproblems as well. In this work, a fully 3D LBM model is developed and applied to the simulation of freesurface impulsive flows. The evolution of the free surface is here tracked by means of a 3Dinterface tracking model and coupled to the traditional LBM algorithm. Dam-breakevents are simulated and LBM numerical results are compared to both analytical andexperimental reference results. The latter are relative to symmetrical dam-break,asymmetrical dam-break, dam-break over a triangular obstacle, dam-break with anisolated building and the laboratory model of the Toce river test case. The accuracy ofthe model is assessed by comparing depth and velocity values, when available,at some gauge locations. The study shows that the LBM provides a remarkablyaccurate description of the phenomena. The results are very promising for futureapplications of this kind of models for the study of realistic hydraulic problems. [ABSTRACT FROM AUTHOR]

Nowadays the Lattice Boltzmann Method (LBM), thanks to its mesoscale approach, is a powerful tool when dealing with upscaling problems in Fluid Dynamics. In this study a numerical investigation on the flow through fractured porous media has been performed, based on a three dimensional LBM model developed at the Engineering Department of the Roma Tre University. Two different kinds of porous matrices, consisting of deterministic and random arrays of spheres, have been considered. The formers have been arranged both as a primitive and body centred cubic system. The latters are characterized both by monodisperse and by polydisperse diameters. In order to calculate the permeability of every considered porous medium, the Darcy's experiment has been simulated. Then a channel has been considered in every porous matrix, giving raise to different fractured porous media. The Darcy's experiment has been repeated with the fractured porous media and the LBM has been used as a numerical lab to verify the ranges of validity of upscaled models based on the analytical solution of flow in equivalent porous media. It has been found that numerical and analytical results are in good agreement when a fractured deterministic porous medium is considered. In this case the order of magnitude of the relative error, defined as the absolute value of the percentage difference between the numerical and analytical velocity on the axis of the channel, is equal to few percents. Moreover, the error decreases with the permeability: the greater the permeability, the smaller the error. LBM numerical results obtained considering random fractured porous media are characterised by a relative error larger than that corresponding to numerical results obtained considering deterministic fractured porous media, being equal permeability and hydrodynamic conditions. Future work is addressed to the understanding of how the parameters characterizing the random fractured porous media affect the results obtained by applying the LBM model and the difference with the reference results. [ABSTRACT FROM AUTHOR]