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Liquid Surfaces with Chaotic Capillary Waves Exhibit an Effective Surface Tension
Steffen Bisswanger1, Henning Bonart1, Pyi Thein Khaing1
1<a href="https://ror.org/05n911h24">Technische Universität Darmstadt</a>, Fachgebiet Nano- und Mikrofluidik, Peter-Grünberg-Straße 10, D-64287 Darmstadt, Germany.
Physical Review Letters
|August 2, 2024
Summary
Chaotic capillary waves, specifically Faraday waves, cause liquid holes to shrink. A new model quantitatively links this shrinkage to wave energy, revealing a dynamic force opposing surface tension.
Area of Science:
- Fluid dynamics
- Nonlinear physics
- Surface phenomena
Background:
- Faraday waves are standing waves formed on a fluid surface subjected to vertical oscillations.
- Capillary waves, driven by surface tension, play a crucial role in fluid behavior.
- Understanding the interplay between waves and liquid interfaces is vital for various applications.
Purpose of the Study:
- To investigate the influence of chaotic capillary waves on the shape of liquid volumes.
- To experimentally and theoretically analyze the shrinkage of a stable hole in a liquid film under Faraday wave excitation.
- To develop a model explaining the observed phenomenon and its underlying physics.
Main Methods:
- Subjecting a liquid film with a stable hole to controlled Faraday wave generation.
- Conducting experimental measurements of hole size dynamics.
- Developing and applying a theoretical model based on the Young-Laplace equation with an effective capillary length.
Main Results:
- Faraday waves induce a measurable shrinkage of the hole in the liquid film.
- The shrinkage can be quantitatively described by incorporating an effective capillary length into the Young-Laplace equation.
- The theoretical model successfully explains the hole shrinkage in the chaotic Faraday wave regime.
- A direct relationship between effective capillary length and wave energy was established.
Conclusions:
- Chaotic Faraday waves exert a dynamic surface force that counteracts the effects of surface tension.
- The effective capillary length is a key parameter linking wave energy to the observed hole shrinkage.
- The findings provide a quantitative understanding of wave-induced modifications to liquid interface shapes.
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