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Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Vortex ring refraction at large Froude numbers
Kerry Kuehn1, Matthew Moeller, Michael Schulz
1Department of Physical Sciences, Wisconsin Lutheran College, Milwaukee, Wisconsin 53226, USA. kerry.kuehn@wlc.edu
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 28, 2010
Summary
Vortex rings impacting fluid interfaces behave differently based on angle and interface strength. Stronger interfaces can cause reflected vortex rings to oscillate, while weaker interfaces lead to downward refraction.
Area of Science:
- Fluid Dynamics
- Interface Physics
Background:
- Vortex rings are fundamental structures in fluid mechanics.
- Interactions between vortex rings and fluid interfaces are crucial in various natural and engineered systems.
Purpose of the Study:
- To experimentally investigate the behavior of vortex rings impacting a density-stratified interface at oblique angles.
- To characterize vortex ring trajectories based on incidence angle and interface strength (Atwood and Froude numbers).
Main Methods:
- Experimental study of axisymmetric vortex rings impacting a gravity-induced interface.
- Varying incidence angles (θ(i)) and interface strength (A/F).
- Observation and categorization of vortex ring trajectories post-impact.
Main Results:
- At grazing incidence angles (θ(i)≳70°), vortex rings either penetrate or reflect based on interface strength.
- Reflected vortices may exhibit damped oscillations before disintegration.
- At smaller incidence angles (θ(i)≲70°), vortices penetrate; they curve towards strong interfaces or refract away from weak interfaces.
- A critical interface strength (log10(A/F) = -2.38 ± 0.05) distinguishes refraction from other behaviors.
Conclusions:
- The trajectory of a vortex ring impacting a fluid interface is highly dependent on both the angle of incidence and the interface strength.
- A critical threshold in interface strength governs whether a penetrating vortex ring refracts away from or curves towards the interface.
- These findings provide a quantitative understanding of vortex-interface interactions.
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