Authors: Francesca Pelusi, Mauro Sbragaglia, Andrea Scagliarini, Matteo Lulli, Massimo Bernaschi, Sauro Succi
Journal: EPL (Europhysics Letters), 2019, 127.3: 34005.
Abstract: We explore the impact of geometrical corrugations on the near-wall flow properties of a soft material driven in a confined rough microchannel. By means of numerical simulations, we perform a quantitative analysis of the relation between the flow rate Φ and the wall stress σw for a number of setups, by changing both the roughness values as well as the roughness shape. Roughness suppresses the flow, with the existence of a characteristic value of σw at which flow sets in. Just above the onset of flow, we quantitatively analyze the relation between Φ and σw . While for smooth walls a linear dependence is observed, steeper behaviours are found to set in by increasing wall roughness. The variation of the steepness, in turn, depends on the shape of the wall roughness, wherein gentle steepness changes are promoted by a variable space localization of the roughness.