Impact of spherical projectiles into a viscoplastic fluid
Hervé Tabuteau1, Darek Sikorski, Simon J de Vet
1Department of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada N6A 3K7.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 9, 2011
Summary
A falling sphere impacting yield-stress fluids causes temporary liquefaction, cavity formation, and jetting. Crater size and shape depend non-monotonically on impact speed, revealing unique fluid dynamics.
Area of Science:
- Fluid dynamics
- Rheology
- Materials science
Background:
- Yield-stress fluids exhibit solid-like behavior below a critical stress threshold.
- Impacts can induce significant shear stresses, leading to temporary fluidization.
Purpose of the Study:
- To investigate the dynamic response of yield-stress fluids to sphere impacts.
- To characterize the resulting cavity dynamics, jet formation, and surface cratering.
Main Methods:
- Experimental study of sphere impacts on a model yield-stress fluid.
- High-speed imaging to capture transient phenomena.
- Analysis of cavity pinch-off, jet evolution, and crater dimensions.
Main Results:
- Impact fluidizes the material near the impact site, creating a transient cavity.
- Cavity collapse can generate a vertical jet, with height dependent on impact velocity.
- Crater diameter exhibits non-monotonic dependence on impact speed, and crater shape evolves with impact dynamics.
Conclusions:
- Yield-stress fluids show distinct responses to impact compared to Newtonian fluids.
- Rheological properties significantly influence cavity pinch-off and jetting phenomena.
- Impact speed is a critical parameter governing crater morphology and fluid behavior.
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