Evidence of shear-dependent boundary slip in newtonian liquids
Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, 89069 Ulm, Germany
2 Department of Applied Mathematics, Australian National University, Canberra 0200 ACT, Australia
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Published online: 5 November 2003
The flow of Newtonian fluids was studied by directly measuring the hydrodynamic drainage force acting on a sphere approaching a flat surface. Our force measurements provide clear evidence of boundary slip and show that the degree of boundary slip is a function of the liquid viscosity and the shear rate. A shear-dependent boundary slippage was also observed in experiments with a polymer (PDMS). The liquids wetted the bounding surfaces either partially or completely. Our results have important consequences for the design of microfluidic devices, and in technological processes, such as lubrication and permeability of microporous media.
PACS: codes. – 47.45.Gx - Slip flows / codes. – 68.37.Ps - Atomic Force Microscopy / codes. – 82.70.Dd - Colloids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003