Titre/Title :
Small scale properties of inertial particles in turbulent flows
Contact :
Achim Wirth
Résumé/Abstract :
I will review some recent advancements about the dynamical and
statistical properties of dilute suspensions of inertial particles,
dispersed in turbulent flows. These are small, but finite size
impurities, with a density contrast with respect to the carrier
fluid. Hence, inertial particles do not simply follow fluid
streamlines, and in the simplest approximation they react to flow
fluctuations via a Stokes viscous drag. Examples of heavy inertial
particles - with density much larger than the fluid-, are liquid water
droplets in air clouds, or some dust and chemicals dispersed in the
atmosphere. Most of the results presented are obtained from Direct
Numerical Simulations of incompressible, homogeneous and isotropic
3D turbulence, seeded with heavy particles. Properties of such
particles will be contrasted with those of tracers, i.e. point-like
particles with negligible mass transported by the fluid. In particular, I
will discuss two effects related to inertia that might enhance
collisions : correlation among particle positions induced by the
carrier flow, and decorrelation between velocities due to their large
inertia.