Abstract: We investigate numerically sedimentation of a drop-shaped particle in an infinitely vertical channel with a LB-DF/FD method. In the method, Navier-Stokes equations are solved by lattice Bohzmann method and fluid-solid interactions are handled by fictitious domain scheme. This work focuses on effects of particle shape factor on friction coefficient and drag coefficient of drop-shaped particle in Reynolds numbers ranging from 10^-2 to 10². Comparison with results of a circular particle is presented. It shows that particle friction coefficient keeps constant as Reynolds number is below 1. It increases as Reynolds number increasing as Reynolds number is greater than 1. Furthermore, it shows that both friction coefficient and drag coefficient of a circular particle are smaller than those of a drop-shaped one as Reynolds number is below 30 while it is greater as Reynolds number is greater than 30. To clarify this issue a detail investigation of pressure distribution around particle is presented.

Key words: lattice Boltzmann method, fictitious domain, drop-shaped particle, frietion coefficient, drag coefncient