Space- and time-resolved stress fluctuations in discontinuous shear thickening suspensions

Discontinuous shear thickening (DST) is associated with a sharp rise of a suspension's viscosity with increasing applied shear rate. A key signature of DST, highlighted in recent studies, is the very large fluctuations of the measured stress as the suspension thickens. Recent work has suggested that these fluctuations are due to the flow-induced growth and percolation of constrained particle networks within the suspension, but the specific localization of these processes are not well understood. To illuminate this connection, we combine simulations of sheared dense frictional suspensions with a local, spatially-resolved analysis derived from experimental boundary stress microscopy measurements. Our study investigates how the microstructural stress fluctuations are non-uniform throughout the sample, and move spatially with respect to time.