Ellipsoidal particles transport and deposition in turbulent channel flows

Ellipsoidal particle transport and deposition in dilute turbulent channel flows are studied. The instantaneous fluid velocity field is generated by the direct numerical simulation (DNS) of the Navier-Stokes equation via a pseudospectral method. The particle equations of motion used include the hydrodynamic forces and torques, the shear-induced lift and the gravitational forces, Euler's four parameters (quaternions) are used for describing the time evolution of particle orientations. Ensembles of ellipsoidal particle trajectories in turbulent channel flows are generated and statistically analyzed. The results are compared with those for spherical particles and their differences are discussed. Effects of particle size and aspect ratio, turbulence near wall eddies, and the gravitational and hydrodynamic forces are studied, The DNS predictions are compared with the available experimental data and earlier sublayer model simulation results and reasonable agreements are observed. (C) 2001 Elsevier Science Ltd. All rights reserved.