Fast moving dynamical contact lines: a capillary ballistic ......fast moving contact lines f 61 Hz...
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Fast moving dynamical contact lines: a capillary ballistic perspective Paul Steen Cornell University work with Yi (James) Xia IMA Workshop “Dynamic contact lines . . .” 27 March 2018 1 Yi Xia JW Mattson JM Ludwicki
Transcript of Fast moving dynamical contact lines: a capillary ballistic ......fast moving contact lines f 61 Hz...
Fast moving dynamical contact lines:a capillary ballistic perspective
Paul SteenCornell University
work with Yi (James) Xia
IMA Workshop “Dynamic contact lines . . .”27 March 2018 1
Yi Xia JW Mattson JM Ludwicki
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fast moving contact lines
fast moving contact lines
61f Hz
1.5a g
1r mm
3/ 10CLCa U
Re / 160CLU r
not‐so‐fast: Huh & Scriven 1971; Dussan V. 1974, Voinov 1976, Tanner 1979, Cox 1986, Hocking 1989, De Gennes, etc
slowed 170x
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H2O
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• fluid inertia vs Young‐Laplace capillarity
• ideal fluid motions – slippery boundaries
capillary ballistics – inertia vs surface tension
Rayleigh half‐drop: exact soln ‐‐ if CA=90, no CA hysteresis.
Borkar et al 1991; Lyubimov 2001, 06; Fayzrakhmanova et al 2009; etc
Carlson et al 2012
physically‐based CL kinetics for fast motions?‐‐ Cox 1998
Re , 0Ca
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damping ratio, ζ
/low damping
high damping
frequency scan – ballistics
frequency scan
/Y X[2,0]
[4,0]
6JFM, Bostwick & phs 2014; Chang et al 2015[2,0]
1 mm
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CL motions – measurement
CL motion
water on low hysteresis Si waferDussan 1979
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parameter details
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more details – systems
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‘mobility’ – say what?
recall Stokes drag
uncompensated Young force contact line drag
mobility
cyclic CL motion
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cyclic motion
clock
phase plane
platform CL displace angle‐displace
cyclic diagram & mobility
~ 3.5 cm/s‐10 degree
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mobility – other systems
• introduce mappings to unfold TD – ‘cyclic diagram’
• measure mobility, purely experimentally
• mobility characterizes CL kinetics – far from stick‐slip
summary
Wettability spectrometer TD
Xia & Steen, JFM 2018
~ 3.5 cm/s‐10 degree
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• fluid inertia balances Young‐Laplace capillarity
• ideal fluid motions – slippery boundaries
• kinetics of CL – contact‐line drag
“The existence of tangential stresses and the impossibility of slip constitute, then, the differences between a real fluid and a theoretically ideal one. In this book we are concerned with the motion of those fluids whose viscosity is small: the phenomena in such motions sometimes approximately agree, sometimes violently disagree, with the predictions of ideal fluid theory…” Sydney Goldstein, “Modern Developments in Fluid Dynamics” volume 1, preface, 1938.
capillary ballistic perspective
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