Abstract:

Granular matter is a collection of a large number of interactive solid particles. For moist granular systems, such as unsaturated soils, interstitial liquid among particles forms complicated connection structures and displays unique flow behaviours, which affect the strength and deformation of moist granular systems. At present, squeeze flow and shear flow between particles with fluid are hard to analyze in fluid mechanics and granular system mechanics. Based on the Reynolds lubrication theory, squeeze flow between two arbitrary rigid spheres with an interstitial bi-viscosity fluid is studied, and the yield surface paradox is avoided. According to the characteristics of stress distribution, the fluid is divided into both yielding and unyielding regions. Along with the variation of parameters, differences between the thicknesses of the two regions are discussed; and the pressure distribution in these regions is analyzed. Furthermore, the change law of the pressure distribution of the fluid and an integral expression of viscous force are derived.

Key words: granular matter, bi-viscosity fluid, squeeze flow, normal viscous force