Non Spherical and Inertial Particles in Couette Turbulent Large Scale Structures

We are studying dispersion of finite-size particles in a turbulent plane Couette flow by numerical simulations. The effect of particle non-sphericity was discussed (particles are neutrally buoyant and shape varies from oblate to prolate, aspect ratio is ranging from 0.5 to 2). Particle dispersion is analyzed also when inertia is considered for different particle densities for spherical particles (while keeping comparable Stokes number). This work yields evidences that the particle distribution in turbulent flow coherent structures is in general correlated to the cycle of regeneration of turbulence in Couette flow (the strongest correlation being for massless bubbles), and that the particle residence time in large scale vortices is equal to the characteristic time scale of the flow regeneration cycle