Modeling of low-capillary number segmented flows in microchannels using OpenFOAM

Modeling of low-Capillary number segmented flows in microchannels is important for the design of microfluidic devices. We present numerical validations of microfluidic flow simulations using the volume-of-fluid (VOF) method as implemented in OpenFOAM. Two benchmark cases were investigated to ensure the reliability of OpenFOAM in modeling complex...

Numerical simulation of particle-laden turbulent channel flow

This paper presents results for the behavior of particle-laden gases in a small Reynolds number vertical channel down flow. Results will be presented for the effects of particle feedback on the gas-phase turbulence and for the concentration profile of the particles. The effects of density ratio, mass loading, and particle inertia will be...

Particle imaging velocimetry experiments and lattice-Boltzmann simulations on a single sphere settling under gravity

A comparison is made between experiments and simulations on a single sphere settling in silicon oil in a box. Cross-correlation particle imaging velocimetry measurements were carried out at particle Reynolds numbers ranging from 1.5 to 31.9. The particle Stokes number varied from 0.2 to 4 and at bottom impact no rebound was observed. Detailed...

Capture and inception of bubbles near line vortices

Motivated by the need to predict vortex cavitation inception, a study has been conducted to investigate bubble capture by a concentrated line vortex of core size rc and circulation ?0 under noncavitating and cavitating conditions. Direct numerical simulations that solve simultaneously for the two phase flow field, as well as a simpler one-way...

Turbulence modulation and drag reduction by spherical particles

This letter reports on the pronounced turbulence modulations and the accompanying drag reduction observed in a two-way coupled simulation of particle-laden channel flow. The present results support the view that drag reduction can be achieved not only by means of polymeric or fiber additives but also with spherical particles.

Resistances for heat and mass transfer through a liquid–vapor interface in a binary mixture

In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid–vapor interface in a binary mixture. We use two methods, the direct calculation from the actual nonequilibrium solution and integral relations, derived earlier. We verify, that integral relations, being a relatively faster and cheaper method, indeed...

Numerical modelling of finite-size particle collisions in a viscous fluid

A general model is presented for short-range hydrodynamic interactions and head-on particle-particle/wall collisions. The model has been embedded in two distinct numerical methods for fully resolved simulation of finite-size particles in a viscous fluid. It accounts for the material properties of the particles and lubrication effects prior to...

On the levitation force in horizontal core-annular flow with a large viscosity ratio and small density ratio

A numerical study has been made of horizontal core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question how the buoyancy force on the core, caused by a density difference between the core and the annular layer, is...