scholarly journals Spreading dynamics and contact angle of completely wetting volatile drops

2018 ◽  
Vol 844 ◽  
pp. 817-830 ◽  
Author(s):  
Etienne Jambon-Puillet ◽  
Odile Carrier ◽  
Noushine Shahidzadeh ◽  
David Brutin ◽  
Jens Eggers ◽  
...  
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
First Principles ◽  
Finite Time ◽  
Time Singularity ◽  
Hydrodynamic Description ◽  
Spreading Dynamics ◽  
Rate Of Evaporation ◽  
Finite Time Singularity ◽  
Evaporating Drops

The spreading of evaporating drops without a pinned contact line is studied experimentally and theoretically, measuring the radius $R(t)$ of completely wetting alkane drops of different volatility on glass. Initially the drop spreads ($R$ increases), then owing to evaporation reverses direction and recedes with an almost constant non-zero contact angle $\unicode[STIX]{x1D703}\propto \unicode[STIX]{x1D6FD}^{1/3}$, where $\unicode[STIX]{x1D6FD}$ measures the rate of evaporation; eventually the drop vanishes at a finite-time singularity. Our theory, based on a first-principles hydrodynamic description, well reproduces the dynamics of $R$ and the value of $\unicode[STIX]{x1D703}$ during retraction.

scholarly journals Finite-time singularity versus global regularity for hyper-viscous Hamilton–Jacobi-like equations

Nonlinearity ◽  
2003 ◽  
Vol 16 (6) ◽  
pp. 1967-1989 ◽  
Author(s):  
Hamid Bellout ◽  
Said Benachour ◽  
Edriss S Titi
Keyword(s):  
Finite Time ◽  
Global Regularity ◽  
Time Singularity ◽  
Finite Time Singularity

Simulation of Spreading Dynamics of a EWOD Droplet With Dynamic Contact Angle and Contact Angle Hysteresis

2009 ◽  
Author(s):  
Fangjun Hong ◽  
Ping Cheng ◽  
Zhen Sun ◽  
Huiying Wu
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
Low Voltage ◽  
Contact Angle Hysteresis ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Dielectric Surface ◽  
Contact Radius ◽  
Droplet Spreading ◽  
Spreading Dynamics

In this paper, the electrowetting dynamics of a droplet on a dielectric surface was investigated numerically by a mathematical model including dynamic contact angle and contact angle hysteresis. The fluid flow is described by laminar N-S equation, the free surface of the droplet is modeled by the Volume of Fluid (VOF) method, and the electrowetting force is incorporated by exerting an electrical force on the cells at the contact line. The Kilster’s model that can deal with both receding and advancing contact angle is adopted. Numerical results indicate that there is overshooting and oscillation of contact radius in droplet spreading process before it ceases the movement when the excitation voltage is high; while the overshooting is not observed for low voltage. The explanation for the contact line overshooting and some special characteristics of variation of contact radius with time were also conducted.

scholarly journals Interacting vacuum at infinity

2019 ◽  
Vol 16 (04) ◽  
pp. 1950052
Author(s):  
G. Kittou
Keyword(s):  
Finite Time ◽  
Central Extension ◽  
Vacuum Model ◽  
Time Singularity ◽  
Attractor Solution ◽  
The One ◽  
Finite Time Singularity

We apply the central extension technique of Poincaré to dynamics involving an interacting mixture of pressureless matter and vacuum near a finite-time singularity. We show that the only attractor solution on the circle of infinity is the one describing a vanishing matter-vacuum model at early times.

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