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The wetting phenomenon at three-phase boundaries (solid, liquid, and gas) affects capillary-gravity wave scattering from barriers, but there is a lack of experimental data and comparison with simulations. The scattering is affected by surface tension and the contact lines at the three-phase boundary. When the solid surface conditions vary, the contact angle and the shape of the meniscus generated by the wetting effect change accordingly. It is possible to measure the influence of the wetting effect on the scattering by coating the barrier surface to be hydrophobic or hydrophilic. Our previous work focused on how the scattering is affected by the portion of the barrier immersed under the water surface with a pinned contact line. In this study, we will coat the barrier surface to experimentally measure how the wetting with different coatings affect the scattering. A comparison of the experimental measurements with numerical simulations of potential flow of the waves will be potentially included.
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Cavitation-induced microjets tuned by channels with alternating wettability patterns
A laser pulse focused near the closed end of a glass capillary partially filled with water creates a vapor bubble and an associated pressure wave. The pressure wave travels through the liquid toward the meniscus where it is reflected, creating a fast, focused microjet. In this study, we selectively coat the hydrophilic glass capillaries with hydrophobic strips along the capillary. The result after filling the capillary is a static meniscus which has a curvature markedly different than an unmodified capillary. This tilting asymmetry in the static meniscus alters the trajectory of the ensuing jets. The hydrophobic strips also influence the advancing contact line and receding contact line as the vapor bubble expands and collapses. We present thirteen different permutations of this system which includes three geometries and four coating schemes. The combination of geometry and coatings influences the jet breakup, the resulting drop size distribution, the trajectory of the jet tip, and the consistency of jet characteristics across trials. The inclusion of hydrophobic strips promotes jetting in line with the channel axis, with the most effective arrangement dependent on channel size.
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- Award ID(s):
- 2153740
- PAR ID:
- 10402561
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- Physics of Fluids
- Volume:
- 35
- Issue:
- 3
- ISSN:
- 1070-6631
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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