To account for meso-scale phenomena in coarse grid simulations, correlation terms appearing in the filtered gas-solid flow equations have to be modeled. Possible approaches to describe filtered gas-solid momentum transfer are evaluated via a mixture speed of sound test. In contrast to the effective drag coefficient closure model for the filtered drag force, the generalized added mass closure model for the correlation between the solid volume fraction and the gas phase pressure gradient shows an acceptable behavior. Furthermore, the generalized added mass may become determining in describing filtered gas-solid momentum transfer when sufficiently coarse grids are used. 3D steady-state riser simulations demonstrate the impact of the generalized added mass based description of filtered gas-solid momentum transfer on the calculated gas-solid flow behavior, in particular on the gas-solid slip velocity profile. (c) 2007 Elsevier Ltd. All rights reserved.