2013/08/31 by Jiajia Zhou, Evgeny S. Asmolov, Friederike Schmid +1 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Anisotropy #Block Copolymer Self-Assembly #Flow (mathematics) #Fluid Dynamics and Thin Films #Gravitational singularity #Limiting #Slip (aerodynamics) #Slippage #Slipping #Streamlines, streaklines, and pathlines #Surface Modification and Superhydrophobicity #physics.flu-dyn
paper · pdf · doi:10.1063/1.4827867
published as J. Chem. Phys. 139, 174708 (2013) · 11 pages, 8 figures, submitted to J. Chem. Phys
arxiv created 2013/10/17 · openalex publication_date 2013/11/06 · arxiv updated 2015/03/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the effective slippage on superhydrophobic grooves with trapezoidal cross-sections of various geometries (including the limiting cases of triangles and rectangular stripes), by using two complementary approaches. First, dissipative particle dynamics (DPD) simulations of a flow past such surfaces have been performed to validate an expression [E. S. Asmolov and O. I. Vinogradova, J. Fluid Mech. 706, 108 (2012)] that relates the eigenvalues of the effective slip-length tensor for one-dimensional textures. Second, we propose theoretical estimates for the effective slip length and calculate it numerically by solving the Stokes equation based on a collocation method. The comparison between the two approaches shows that they are in excellent agreement. Our results demonstrate that the effective slippage depends strongly on the area-averaged slip, the amplitude of the roughness, and on the fraction of solid in contact with the liquid. To interpret these results, we analyze flow singularities near slipping heterogeneities, and demonstrate that they inhibit the effective slip and enhance the anisotropy of the flow. Finally, we propose some guidelines to design optimal one-dimensional superhydrophobic surfaces, motivated by potential applications in microfluidics.