Our experiments showed that the flow transitions when a neutrally buoyant suspension of finite size particles (volume fraction = 0.1) is sheared between a rotating inner cylinder and a stationary concentric outer cylinder, with the increase in Reynolds number (Re, based on the inner cylinder rotation rate), follow the sequence circular Couette flow (CCF) – Ribbons (RIB) – spiral vortex flow (SVF) – Taylor vortex flow (TVF) – wavy vortex flow (WVF). Note that for a
Newtonain fluid with out particles the transition follows CCF – TVF – WTV. The presense of particles produced the non-axisymmetric time modualating flow structures (SVF and RIB) and reduced the Re corresponding to all the flow transitions. This deviation from the behavior of the Newtonian fluid with no particles increased with the increase in particle size and concentration.