Suspension rheology

Suspension rheology relates particle concentration, particle pressure, shear stress, deformation rate, and fluid migration in a mixture of particles and a liquid.

In the non-interacting dilute limit, the particle contribution to bulk stress is number density times the orientation average of the particle stresslet tensor. Alignment, tumbling, rotational diffusion and interactions determine the orientational distribution and hence the excess viscosity.

Jamming is the loss of the ability of a dense disordered material to flow as its particle fraction or applied confinement reaches a critical state.

The viscous number $I_v=\eta |\dot{\gamma }|/p_s$ compares viscous shear stress with particle pressure in a dense suspension.

Shear-induced dilation is the tendency of a dense granular or suspended-particle packing to increase its volume under shear. In a saturated confined system it requires pore-fluid migration and can delay stress adjustment.