Jump to content

Preferential concentration

From Wikipedia, the free encyclopedia
Preferential concentration of 50 micron hollow glass particles in the homogeneous isotropic turbulence without mean flow when the Stokes number is 1

Preferential concentration[1][2] is the tendency of dense particles in a turbulent fluid to cluster in regions of high strain (low vorticity) due to their inertia. The extent by which particles cluster is determined by the Stokes number, defined as , where and are the timescales for the particle and fluid respectively; note that and are the mass densities of the fluid and the particle, respectively, is the kinematic viscosity of the fluid, and is the kinetic energy dissipation rate of the turbulence. Maximum preferential concentration occurs at . Particles with follow fluid streamlines and particles with do not respond significantly to the fluid within the times the fluid motions are coherent.

Systems that can be strongly influenced by the dynamics of preferential concentration are aerosol production of fine powders, spray, emulsifier, and crystallization reactors, pneumatic devices, cloud droplet formation, aerosol transport in the upper atmosphere, and even planet formation from protoplanetary nebula.

References

[edit]
  1. ^ "Analyzing preferential concentration and clustering of inertial particles in turbulence".
  2. ^ "Preferential concentration of particles by turbulence".
[edit]