15 research outputs found
Numerical simulations of compressible Rayleigh-Taylor turbulence in stratified fluids
We present results from numerical simulations of Rayleigh-Taylor turbulence,
performed using a recently proposed lattice Boltzmann method able to describe
consistently a thermal compressible flow subject to an external forcing. The
method allowed us to study the system both in the nearly-Boussinesq and
strongly compressible regimes. Moreover, we show that when the stratification
is important, the presence of the adiabatic gradient causes the arrest of the
mixing process.Comment: 15 pages, 11 figures. Proceedings of II Conference on Turbulent
Mixing and Beyond (TMB-2009
Permeability of self-affine rough fractures
The permeability of two-dimensional fractures with self-affine fractal
roughness is studied via analytic arguments and numerical simulations. The
limit where the roughness amplitude is small compared with average fracture
aperture is analyzed by a perturbation method, while in the opposite case of
narrow aperture, we use heuristic arguments based on lubrication theory.
Numerical simulations, using the lattice Boltzmann method, are used to examine
the complete range of aperture sizes, and confirm the analytic arguments.Comment: 11 pages, 9 figure
Simulation of Flow of Mixtures Through Anisotropic Porous Media using a Lattice Boltzmann Model
We propose a description for transient penetration simulations of miscible
and immiscible fluid mixtures into anisotropic porous media, using the lattice
Boltzmann (LB) method. Our model incorporates hydrodynamic flow, diffusion,
surface tension, and the possibility for global and local viscosity variations
to consider various types of hardening fluids. The miscible mixture consists of
two fluids, one governed by the hydrodynamic equations and one by diffusion
equations. We validate our model on standard problems like Poiseuille flow, the
collision of a drop with an impermeable, hydrophobic interface and the
deformation of the fluid due to surface tension forces. To demonstrate the
applicability to complex geometries, we simulate the invasion process of
mixtures into wood spruce samples.Comment: Submitted to EPJ