Direct numerical simulation of one-sided forced thermal convection in plane channels

We carry out direct numerical simulations (DNS) of turbulent flow and heat transfer in pressure-driven plane channels, by considering cases with heating on both walls, as well as asymmetric heating limited to one of the channel walls. Friction Reynolds numbers up to are considered, and Prandtl numbers from to, the temperature field being...

Direct numerical simulation of forced thermal convection in square ducts up to Reτ≈2000

We carry out direct numerical simulations (DNS) of flow in a turbulent square duct by focusing on heat transfer effects, considering the case of unit Prandtl number. Reynolds numbers up to are considered that are much higher than in previous studies, and that yield clear scale separation between inner- and outer-layer dynamics. Close...

Droplet-Turbulence interactions and quasi-equilibrium dynamics in turbulent emulsions

We perform direct numerical simulations (DNS) of emulsions in homogeneous isotropic turbulence using a pseudopotential lattice-Boltzmann (PP-LB) method. Improving on previous literature by minimizing droplet dissolution and spurious currents, we show that the PP-LB technique is capable of long stable simulations in certain parameter regions....

Turbulence attenuation in simultaneously heated and cooled annular flows at supercritical pressure

Heated or cooled fluids at supercritical pressure show large variations in thermophysical properties, such as the density, dynamic viscosity and molecular Prandtl number, which strongly influence turbulence characteristics. To investigate this, direct numerical simulations were performed of a turbulent flow at supercritical pressure (CO2 at 8...

Interphasial energy transfer and particle dissipation in particle-laden wall turbulence

Transfer of mechanical energy between solid spherical particles and a Newtonian carrier fluid has been explored in two-way coupled direct numerical simulations of turbulent channel flow. The inertial particles have been treated as individual point particles in a Lagrangian framework and their feedback on the fluid phase has been incorporated in...

A lattice Boltzmann study on the drag force in bubble swarms

Turbulence Simulation via the Lattice-Boltzmann Method on Hierarchically Refined Meshes

In the present work the application of hierarchical grid refinement for the Lattice-Boltzmann Method (LBM) to simulate turbulent flows has been investigated. A transformation and interpolation scheme has been developed based on a volumetric approach, independent of a specific collision model and therefore, generally applicable to all variants of...

Local grid refinement in large-eddy simulations. Large-scale numerical modelling of problems involving the Navier-Stokes equations