Experimental study on internal flow structure and dynamics of dense liquid-particle flow down inclined channel

Dense granular flows widely exist in the environment and industry where inter-particle interactions play essential role. Studying the flow behaviour is important for a better understanding and more scientific description of the granular rheology. This paper experimentally investigates liquid-particle mixture dense flows down an inclined channel with bumpy-frictional base. The refractive index matching method is used which permits the determination of the internal flow information, including the velocity, shear rate, granular temperature and solid concentration. It is observed that the wall influence is minor at the observing position. The pressure and shear stress obtained from the integration of the solid concentration matches well with the prediction of the kinetic theory. The particle interaction pattern is analysed from the rheology properties and a coherence length approach. The flow is found to be rheologically stratified, with the near-bottom being collision-dominated and the near-surface being friction-dominated. The bottom pore pressure and stress are also directly measured and analysed in combination with the internal kinetic properties.