This work focuses on subgrid-scale (SGS) modeling for finite-difference large-eddy simulations, employing filters in physical space. When a filter space is used, an overlap allowed between the unresolved and resolved scales. For such filter, all three terms classical decomposition of SGS stress tensor are present: Leonard cross-terms, due to scales, true Reynolds tensor, expressing pure effect small A dynamic model proposed, simulation incompressible compressible flows which cross-parts...

To tackle climate change, we need to incorporate renewable energy sources on a large scale. One potential solution is the use of hydrogen, as an alternative vector that can be burnt in existing devices with little modification. Hydrogen produced from excess wind and solar power, ammonia, hydrogen carrier, very appealing it easily liquified distributed through infrastructure. This study aims explore feasibility using ammonia–hydrogen mixtures industrial settings. exploration made by modeling...

The steady engulfment regime in a fully three-dimensional micro T-mixer is investigated. This of significant interest for applications since it implies high mixing between the flow streams entering device. Direct numerical simulations are first used to characterize this regime. In particular, main vortical structures typical and their effects on Three-dimensional linear stability analysis successively applied characterization instability leading critical Reynolds number global unstable mode...

We describe the results of a numerical and experimental investigation aimed at assessing performance control method to delay boundary layer separation consisting introduction on surface contoured transverse grooves, i.e. small cavities with an appropriate shape orientated incoming flow. The grooves their depth – which must be significantly smaller than thickness are chosen so that flow recirculations present within steady stable. This passive strategy is applied axisymmetric bluff body...

An overview of the mixing performances micro T mixers operating with a single fluid is presented. The focus on relationship between flow features and mixing. Indeed, are characterized by variety regimes for increasing Reynolds numbers; they briefly described, in particular terms three-dimensional vorticity field, which can explain different performances. effects changes aspect ratio channels also reviewed. role instability sensitivity analyses highlighting mechanisms onsets then described....

Large-Eddy Simulations were conducted to investigate accelerated flows around a square cylinder. The study explores flow characteristics for Gaussian-type accelerations of the inflow within range Reynolds numbers Re=1.720×104 Re=6.536×104. Three different acceleration intensities same Re have been considered. For all analyzed values, time cells with constant frequency in vortex shedding identified agreement experimental findings Brusco et al. (2022a). temporal behavior vorticity field...

The problem of accurate Eulerian–Lagrangian modeling inertial particle dispersion in large-eddy simulation (LES) turbulent wall-bounded flows is addressed. We run direct numerical (DNS) channel flow at shear Reynolds number Reτ=150 and corresponding a priori posteriori LES on two coarser grids. For each field, we tracked swarms particles with different inertia to examine the behavior statistics, specifically focusing preferential segregation accumulation wall. Our object discuss necessity...

Two arrow-shaped micro-mixers, obtained from the classical T-shaped geometry by tilting downward inlet channels, are considered herein. The two configurations, having different angle values, have been chosen since they show significantly flow topologies and mixing performances at low Reynolds numbers. In present paper, we use both experimental visualizations direct numerical simulations to shed light on behavior of configurations for larger numbers, which mixers unsteady periodic flows,...

Experiments, i.e. micro-PIV and flow visualization, direct numerical simulations, are used jointly to investigate how stratification affects mixing chemical reaction in a T-shaped microreactor fed with two miscible liquids exhibiting small density difference. The work analyzes the dependence of degree on Reynolds number correlates yield Damk\"ohler help devise strategies for practical operation microreactors fluids interest.