On the motion of nonspherical particles in a turbulent flow

Noninteracting rigid spheroids are considered which are suspended in a homogeneous turbulent flow. A renormalized expansion is used to derive a kinetic equation whose coefficients are determined by the Lagrangian correlation function of the turbulent velocity field and by the translational diffusion coefficient D and the orientational relaxation frequency ωu of the spheroid. For isotropic turbulence, coupled integral relations for D and ωu are obtained, applying the moment method. These are solved numerically for different correlation frequencies of the energy spectrum. The effect of the renormalization and the resulting coupling between the translational and orientational relaxation are discussed.