Transition from frictional to viscous regime for granular suspensions

From a series of experiments performed on fluid-bead mixtures, we show that a transition occurs between a frictional regime (at low rates) and a visco us regime (at high rates). The examination of various interaction types dem onstrates that such a transition is probably due to the shear-induced conta ct lubrication. (C) Academie des sciences/Elsevier, Paris.