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K.F. Gurski and G.B. McFadden. The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems. Introduction to the Rayleigh instability Anisotropic surface energy 2-D equilibrium shapes Rayleigh instability for anisotropic surface energy
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K.F. Gurski and G.B. McFadden The Effect of Surface Tension Anisotropy on the Rayleigh Instability in Materials Systems • Introduction to the Rayleigh instability • Anisotropic surface energy • 2-D equilibrium shapes • Rayleigh instability for anisotropic surface energy • Conclusions and future work Mathematical and Computational Sciences Division National Institute of Standards and Technology Thanks to S.H. Davis NASA Microgravity, NSF NIRT (NWU)
Inkjet Printing From Pimbley et al. [1977]. Breakup of a liquid jet into drops.
Cellular Growth during Directional Solidification From Kurowski et al. [1989]. Breakup of liquid grooves into drops during solidification of CBr4.
Instability of Rod Morphology During Monotectic Growth From Majumdar et al. [1996]. Breakup of aligned rods into drops during cooperative monotectic growth of Zinc-Bismuth..
Nanobridge From Kondo et al. [1997]. Free-standing bridge formed by using electron beam irradiation in an ultrahigh vacuum electron microscope.
Quantum Wires From Chen et al. [2000]. STM topographs showing ErSi2 (011) nanowires grown on a flat Si(001) substrate. The Si terraces increase in height from deep blue to green.
Possible Reasons for Enhanced Stability • Quantum effects (Kassubek et al. [2001]). • Elastic effects with substrate (Chen et al. [2000]) • Stabilization by contact angle (McCullum et al. [1996]) • Radial thermal gradients (McFadden et al. [1993]) • Surface energy anisotropy (this work)
Cubic Material 3-D Equilibrium Shapes for -1/18 < 4 <1/12 High-Symmetry Orientations: [001], [011], [111]
Numerics • SLEIGN2: Associated Sturm–Liouville Solver • Spectral Decomposition with RS (a real symmetric eigenvalue routine)
[001] Orientation 4 = 1/12 0 -1/18 < 4 < 1/12 1 2
[011] Orientation -1/18 < 4 < 1/12
011 Orientation 0 1 2
Conclusions • Anisotropic surface energy plays a significant role in the stability of a rod. • Both the magnitude and sign of the anisotropy determine whether the contribution promotes or suppresses the Rayleigh instability. • Different cubic orientations react quite differently to the surface tension anisotropy. Future Work • Missing orientations • Contact angles • Elastic effects
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