Particles are present in many natural and industrial multiphase flows. In most practical cases, particle shape is not spherical, leading to additional difficulties for numerical studies. this paper, DNS of turbulent channel flows with finite-size prolate spheroids performed. The geometry includes a straight wall-bounded at frictional Reynolds number 180 seeded particles. Three different shapes considered, either spheroidal (aspect ratio λ=2 or 4) spherical (λ=1). Solid-phase volume fraction...

The present study focuses on the behaviour of fully resolved oblate spheroids in turbulent channel flows using lattice Boltzmann method (LBM). Mean and maximum drag reductions 1.3 % 4.4 %, respectively, are observed at a solid-phase volume fraction 10 by aspect ratio $\unicode[STIX]{x1D706}=1/3$ equivalent diameter $D_{eq}/H=1/6.5$ . spheres found to be different near-wall region, where spheroids, contrast spheres, do not augment turbulence. Strong reduction spanwise wall-normal fluid...

In many cases, multi-species and/or thermal flows involve large discrepancies between the different diffusion coefficients involved — momentum, heat and species diffusion. context of classical passive scalar lattice Boltzmann (LB) simulations, scheme is quite sensitive to such discrepancies, as relaxation flow fields are tied together through their common spacing time-step size. This in turn leads at least one coefficient, [Formula: see text] being either very close 0.5 or much larger than...

The resolution of small near-wall eddies encountered in high-Reynolds number flows using large eddy simulation (LES) requires very fine meshes that may be computationally prohibitive. As a result, the use wall-modeled LES as an alternative is becoming more popular. In this paper, domain decomposition (NDD) approach was originally developed for Reynolds-averaged Navier–Stokes simulations (RANSs) extended to hybrid RANS/LES zonal decomposition. algorithm implemented two stages. First, solution...

Many natural and industrial processes involve transport of solid particles. This research reports sedimentation modes a single cold elliptical particle with an aspect ratio 2 in narrow hot channels. Prior on settling non-isothermal particles was limited to wide vertical A constant non-dimensional temperature Tp∗=0 initial orientation θ0=π/3 between its major axis horizontal is released fluid. Fluid Prandtl number 7, Tf,0∗=1. Simulations are based in-house lattice-Boltzmann solver two...

To mitigate the high computational cost associated with resolving small near-wall eddies in large eddy simulation (LES) while achieving acceptable accuracy, this work extends implicit domain decomposition (INDD) method to a hybrid Reynolds-averaged Navier–Stokes (RANS)/LES zonal approach. In framework, LES solution is first computed using Robin-type (slip) wall boundary condition on coarse mesh. This then iteratively corrected region based an updated derived from simplified one-dimensional...

The impact of the collision model employed when simulating fully resolved particles interacting in a fluid is investigated present study. We are using for this purpose p seudo-spectral compressib le Direct Numerical Simulation (DNS) code based on Navier-Stokes equation as well Lattice-Boltzmann Method (LBM), developed our group and coupled with direct-forcing Immersed Boundary (IBM) to describe particles. Most corresponding literature assumes that does not have significant flow field....

Near-wall turbulence modelling with the use of large eddy simulation (LES) is computationally costly since it requires very fine meshes to resolve small eddies near wall. In this research, we a hybrid zonal RANS/LES decomposition that based on near-wall domain method initially developed for Reynolds averaged Navier-Stokes equations (RANS). The solution achieved in two stages. First, computed entire region using LES coarse grid specially derived slip boundary conditions at then recomputed...

Near-wall turbulence modelling with the use of large eddy simulation (LES) is computationally costly since it requires very fine meshes to resolve small eddies near wall. In this research, we a hybrid zonal RANS/LES decomposition that based on near-wall domain method initially developed for Reynolds averaged Navier-Stokes equations (RANS). The solution achieved in two stages. First, computed entire region using LES coarse grid specially derived slip boundary conditions at then recomputed...