It is well-known that the bio-inspired sharkskin covering the original pattern has the apparent drag reduction function in the turbulent flowing stations, which can be regarded as "sharkskin effect", and it has progressively been put application into the fluid engineering with obtaining great profits. In this paper, the anisotropic wetting phenomena on sharkskin are discovered, the contact angles and rolling angles on different orientations are not the same. In addition, the hydrodynamic experiments on different sharkskin surfaces are conducted, and the experimental results illustrate that the super-hydrophobic and drag-reducing properties on deformed biological surfaces are improved to some extent compared to the original morphology, which has important significance to expand its practical applications.
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http://dx.doi.org/10.1016/j.micron.2015.12.004 | DOI Listing |
J Colloid Interface Sci
January 2025
School of Engineering, University of Liverpool, Liverpool, L69 3GH, United Kingdom.
Hypothesis: We hypothesise that superhydrophobic surfaces can achieve effective interfacial slip and drag reduction even under non-Newtonian, shear-thinning fluid flows. Unlike Newtonian fluids, where slip is primarily influenced by viscosity and surface tension, we anticipate that the shear-thinning nature of these fluids may enhance slip length and drag reduction.
Experiments And Numerical Analysis: The superhydrophobic surfaces used in this study, featuring a dual-scale random topography, were fabricated via a spray coating process, and low-concentration xanthan gum solutions (50-250 ppm) were used as model shear-thinning fluids of low elasticity.
Biomimetics (Basel)
January 2025
Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, MA 02747, USA.
The gas (or plastron) trapped between micro/nano-scale surface textures, such as that on superhydrophobic surfaces, is crucial for many engineering applications, including drag reduction, heat and mass transfer enhancement, anti-biofouling, anti-icing, and self-cleaning. However, the longevity of the plastron is significantly affected by gas diffusion, a process where gas molecules slowly diffuse into the ambient liquid. In this work, we demonstrated that plastron longevity could be extended using a gas-soluble and gas-permeable polydimethylsiloxane (PDMS) surface.
View Article and Find Full Text PDFBiomimetics (Basel)
January 2025
Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA.
Superhydrophobic coatings are beneficial for applications like self-cleaning, anti-corrosion, and drag reduction. In this study, we investigated the impact of surface geometry on the static, dynamic, and sliding contact angles in the Cassie-Baxter state. We used fluoro-silane-treated silicon micro-post patterns fabricated via lithography as model surfaces.
View Article and Find Full Text PDFJ R Soc Interface
January 2025
Laboratoire Matière et Systèmes Complexes, CNRS, Université Paris Cité, Paris, France.
Many swimmers, especially small- to medium-sized animals, use intermittent locomotion that differs from continuous swimming of large species. This type of locomotion, called burst and coast, is often associated with an energetic advantage. In this work, we investigate the intermittent locomotion inspired by fish locomotion but applied to a propeller.
View Article and Find Full Text PDFNatl Sci Rev
February 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
In the evolving landscape of materials science, the journey from traditional composite materials to liquid-solid composites has marked a significant shift. Composite materials, typically solid state, have long been the cornerstone of many applications due to their structural stability and mechanical properties. However, the emergence of liquid-solid composites has introduced a new paradigm, leveraging the dynamic composite interfaces and fluidic nature of liquids.
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