TY - JOUR
T1 - On the distinguished limits of the Navier slip model of the moving contact line problem
AU - Ren, Weiqing
AU - Trinh, Philippe H.
AU - E, Weinan
N1 - Publisher Copyright: © © 2015 Cambridge University PressÂ.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - When a droplet spreads on a solid substrate, it is unclear what the correct boundary conditions are to impose at the moving contact line. The classical no-slip condition is generally acknowledged to lead to a non-integrable singularity at the moving contact line, which a slip condition, associated with a small slip parameter, λ, serves to alleviate. In this paper, we discuss what occurs as the slip parameter, λ, tends to zero. In particular, we explain how the zero-slip limit should be discussed in consideration of two distinguished limits: one where time is held constant, t=O(1), and one where time tends to infinity at the rate t=O(|log λ|). The crucial result is that in the case where time is held constant, the λ → 0 limit converges to the slip-free equation, and contact line slippage occurs as a regular perturbative effect. However, if λ → 0 and t → ∞, then contact line slippage is a leading-order singular effect.
AB - When a droplet spreads on a solid substrate, it is unclear what the correct boundary conditions are to impose at the moving contact line. The classical no-slip condition is generally acknowledged to lead to a non-integrable singularity at the moving contact line, which a slip condition, associated with a small slip parameter, λ, serves to alleviate. In this paper, we discuss what occurs as the slip parameter, λ, tends to zero. In particular, we explain how the zero-slip limit should be discussed in consideration of two distinguished limits: one where time is held constant, t=O(1), and one where time tends to infinity at the rate t=O(|log λ|). The crucial result is that in the case where time is held constant, the λ → 0 limit converges to the slip-free equation, and contact line slippage occurs as a regular perturbative effect. However, if λ → 0 and t → ∞, then contact line slippage is a leading-order singular effect.
KW - contact lines
KW - lubrication theory
KW - thin films
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U2 - https://doi.org/10.1017/jfm.2015.173
DO - https://doi.org/10.1017/jfm.2015.173
M3 - Article
SN - 0022-1120
VL - 772
SP - 107
EP - 126
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
ER -