Ellipsoidal particles transport and deposition in turbulent channel flows

Ellipsoidal particle transport and deposition in dilute turbulent channel f lows are studied. The instantaneous fluid velocity field is generated by th e direct numerical simulation (DNS) of the Navier-Stokes equation via a pse udospectral method. The particle equations of motion used include the hydro dynamic forces and torques, the shear-induced lift and the gravitational fo rces, Euler's four parameters (quaternions) are used for describing the tim e evolution of particle orientations. Ensembles of ellipsoidal particle tra jectories in turbulent channel flows are generated and statistically analyz ed. The results are compared with those for spherical particles and their d ifferences are discussed. Effects of particle size and aspect ratio, turbul ence near wall eddies, and the gravitational and hydrodynamic forces are st udied, The DNS predictions are compared with the available experimental dat a and earlier sublayer model simulation results and reasonable agreements a re observed. (C) 2001 Elsevier Science Ltd. All rights reserved.