Turbulence and inertial effects in a porous bed: DNS and flow analysis
Résumé
Direct numerical simulation (DNS) of pore-scale turbulence is performed in a unit cell of a face-centered cubic lattice at three different pore Reynolds numbers (300, 500 and 1000). Eulerian statistics of mean and fluctuating velocity field, turbulent kinetic energy (TKE) budget, and single and two-point correlations are obtained to quantify the effect of confinement on turbulence in porous media. Large acceleration and deceleration regions in the flow field yield negative TKE production and flow features similar to a jetimpingement-like flow. The flow field is also analyzed using angular Lagrangian statistics (Bos et al. 2015) of fluid particles to study the temporal evolution of the direction change and its asymptotic behavior, the latter being hypothesized to be dependent on the pore geometry. A stochastic Monte Carlo-based model is developed to provide a reasonable prediction of this asymptotic curvature angle. The Eulerian and Lagrangian correlations are used to characterize pore-scale dispersion.
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