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Updated: Mar 20, 2026
06:07
Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
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Experimental evidence for granular shear-flow instability in the Epstein regime
Holly L Capelo1, Jean-David Bodénan2,3, Martin Jutzi1
1Physics institute, Space Research and Planetary Sciences, University of Bern, Bern, Switzerland.
Communications Physics
|March 19, 2026
Summary
Researchers observed a granular shear flow instability in microgravity, mimicking the Kelvin-Helmholtz instability. This finding advances our understanding of planetesimal formation in protoplanetary discs.
Area of Science:
- Astrophysics
- Fluid Dynamics
- Planetary Science
Background:
- Protoplanetary disc models study planetesimal formation.
- Dust-gas flows create shear layers prone to instability.
- Earth-based experiments face gravity-driven buoyancy challenges.
Purpose of the Study:
- Investigate granular shear flow instability in microgravity.
- Provide a benchmark for two-fluid theories in planet formation.
- Understand dust particle behavior in protoplanetary discs.
Main Methods:
- Utilized particle image velocimetry.
- Studied low-pressure dust-gas mixtures.
- Conducted experiments in microgravity with Knudsen numbers up to 10.
Main Results:
- Observed a granular shear flow instability.
- Characterized the instability by a periodic velocity field.
- Modeled the instability as a Kelvin-Helmholtz (KH) instability.
Conclusions:
- The observed instability resembles Kelvin-Helmholtz instability.
- Experimental results offer a benchmark for two-fluid theories.
- Findings are relevant to understanding planet formation processes.
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