Drag of wall-bounded flows

Abstract

The work in this thesis was carried out at the Physics of Fluids group, and the Soft matter, Fluidics and Interfaces Group of the Faculty of Science and Technology of the University of Twente. This thesis was financially supported by the project "GasDrive: Minimizing emissions and energy losses at sea with LNG combined prime movers, underwater exhausts and nano hull material" (project 14504) of the Netherlands Organisation for Scientific Research (NWO), domain Applied and Engineering Sciences (TTW). Dutch title:Frictie van wandbegrenste stromingen Cover: Microscopy image of silica wafer in which double re-entrant cavities are etched (see chapter 1), with a natural di↵raction pattern of the incident light at the surface. Image taken by Jan van Nieuwkasteele.

Insect-inspired breathing interfaces: investigating robustness of coating-free gas entrapping microtextured surfaces under pressure cycles

“…Under the constraints of present and future regulations on perfluoroalkyl substances 46,47 , DRCs may afford a coating-free alternative for applications that require omniphobicity. Proof-of-concept demonstrations for DRCs been recently reported under hydrostatic scenarios, which have helped in mitigating cavitation erosion 19 , enhancing heat transfer 34,76 , microfluidics applications 77 , separation and purification technologies 48,78 , frictional drag reduction 79 , and oscillating-bubble-powered microswimmer applications 80 . As the prospect of translating these interesting findings into practical solutions matures, concerted efforts will be needed to investigate the effects of pressure cycling on GEMS of varying depth, as well as the collective behavior of DRC arrays, with a wide range of probe liquids, especially those with low surface tensions.…”