Lasting effects of discontinuous shear thickening in cornstarch suspensions upon flow cessation

Abstract

Discontinuous shear-thickening (DST) fluids exhibit complex stress relaxation upon flow cessation. We investigate the relaxation behavior of dense cornstarch suspensions via rotational rheometry and find that the relaxation timescales and the residual stress increase with the apparent viscosity measured in the DST state prior to the flow cessation. Within the framework that attributes DST to the lubricated-to-frictional transition of interparticle contact, our results indicate that the lasting effects of the DST state arise from partial retention of frictional force chains after flow cessation.