Particles in turbulent separated flow over a bump: effect of the Stokes number and lift force
arXiv:1907.02270 · doi:10.1063/1.5119103
Abstract
Particle-laden turbulent flow that separates due to a bump inside a channel is simulated to analyse the effects of the Stokes number and the lift force on the particle spatial distribution. The fluid friction Reynolds number is approximately 900 over the bump, the highest achieved for similar computational domains. A range of particle Stokes numbers are considered, each simulated with and without the lift force in the particle dynamic equation. When the lift force is included a significant difference in the particle concentration, in the order of thousands, is observed in comparison with cases where the lift force is omitted. The greatest deviation is in regions of high vorticity, particularly at the walls and in the shear layer but results show that the concentration also changes in the bulk of the flow away from the walls. The particle behaviour changes drastically when the Stokes number is varied. As the Stokes number increases, particles bypass the recirculating region that is formed after the bump and their redistribution is mostly affected by the strong shear layer. Particles segregate at the walls and particularly accumulate in secondary recirculating regions behind the bump. At higher Stokes numbers, the particles create reflection layers of high concentration due to their inertia as they are diverted by the bump. The fluid flow is less influential and this enables the particles to enter the recirculating region by rebounding off walls and create a focus of high particle concentration.
arXiv comment8 pages, 9 figures, submitted to Physics of Fluids
References in corpus (10)
- Guidelines for the formulation of Lagrangian stochastic models for particle simulations of single-phase and dispersed two-phase turbulent flows
- Modification of particle-laden near-wall turbulence: effect of Stokes number
- Mechanisms for the clustering of inertial particles in the inertial range of isotropic turbulence
- Effect of geometry and Reynolds number on the turbulent separated flow behind a bulge in a channel
- Particle transport in turbulent curved pipe flow
- Statistical model for the orientation of non-spherical particles settling in turbulence
- Lagrangian filtered density function for LES-based stochastic modelling of turbulent dispersed flows
- Exact regularized point particle (ERPP) method for particle-laden wall-bounded flows in the two-way coupling regime
- Turbulence modulation in heavy-loaded suspensions of tiny particles
- Optimal control of a separated boundary-layer flow over a bump