Simple dimensional arguments are used in establishing three different regimes of particle time scale, where explicit expression for particle Reynolds number and Stokes number are obtained as a function of nondimensional particle size (d/eta) and density ratio. From a comparative analysis of the different computational approaches available for turbulent multiphase flows it is argued that the point-particle approach is uniquely suited to address turbulent multiphase flows where the Stokes number, defined as the ratio of particle time scale to Kolmogorov time scale (tau(p)/tau(k)), is greater than 1. The Stokes number estimate has been used to establish parameter range where point-particle approach is ideally suited. The point-particle approach can be extended to handle "finite-sized" particles whose diameter approach that of the smallest resolved eddies. However, new challenges arise in the implementation of Lagrangian-Eulerian coupling between the particles and the carrier phase. An approach where the inter-phase momentum and energy coupling can be separated into a deterministic and a stochastic contribution has been suggested. (C) 2009 Elsevier Ltd. All rights reserved.