Spreading Dynamics
If a drop is placed on a smooth, horizontal surface, it is generally not in the equilibrium state. Hence, it spreads until an equilibrium contact radius is reached (partial wetting). While taking into account capillary, gravitational and viscous contributions, the drop radius as a function of time can be expressed as
For the complete wetting situation, the drop radius at any time during the spreading process is given by
where
-
- γLG = Surface tension of the fluid
- V = Drop volume
- η = Viscosity of the fluid
- ρ = Density of the fluid
- g = Gravitational constant
- λ = Shape factor λ=37.1 m-1
- t0 = Experimental delay time
- re = Drop radius in the equilibrium
- γLG = Surface tension of the fluid
Read more about this topic: Wetting
Famous quotes containing the words spreading and/or dynamics:
““Vengeance upon the murderers,” the cry goes up,
“Vengeance for Jacques Molay.” In cloud-pale rags, or in lace,
The rage-driven, rage-tormented, and rage-hungry troop,
Trooper belabouring trooper, biting at arm or at face,
Plunges towards nothing, arms and fingers spreading wide
For the embrace of nothing....”
—William Butler Yeats (1865–1939)
“Anytime we react to behavior in our children that we dislike in ourselves, we need to proceed with extreme caution. The dynamics of everyday family life also have a way of repeating themselves.”
—Cathy Rindner Tempelsman (20th century)