Volume 127, Number 3, August 2019
|Number of page(s)||7|
|Section||Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics|
|Published online||19 September 2019|
On the impact of controlled wall roughness shape on the flow of a soft material
1 Dipartimento di Fisica, Università di Roma “Tor Vergata” and INFN - Via della Ricerca Scientifica 1, I-00133 Rome, Italy
2 Istituto per le Applicazioni del Calcolo, CNR - Via dei Taurini 19, I-00185 Rome, Italy
3 Department of Applied Physics, The Hong Kong Polytechnic University - Hong Kong, China
4 Center for Life Nano Science Sapienza, Istituto Italiano di Tecnologia - Viale Regina Elena 295, I-00161 Rome, Italy
Received: 3 April 2019
Accepted: 30 July 2019
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 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 at which flow sets in. Just above the onset of flow, we quantitatively analyze the relation between Φ and . 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.
PACS: 47.57.-s – Complex fluids and colloidal systems / 83.60.La – Viscoplasticity; yield stress / 02.70.-c – Computational techniques; simulations
© EPLA, 2019
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