We consider steady, fully-developed flows of deformable, inelastic grains driven by gravity
between identical bumpy walls. Using constitutive relations from extended kinetic theory
(EKT) for the erodible bed near the centreline and the collisional flow between the surfaces
of the bed and the walls, we calculate the fields of mean velocity, fluctuation velocity and
solid volume fraction across the chute. We consider both situations in which the solid
volume fraction at and near the centreline is high enough to form a bed and when it is not.
We compare results predicted by EKT with recent discrete element simulations results,
and obtain very good agreement.