HI:

does sombody know a good reference for the surface tensions!

regards

R. F. Probstein, Physicochemical Hydrodynamics - An Introduction, Wiley Interscience, 1994

Huh. C., Scriven LE. Hydrodynamic model of steady movement of a solid/liquid/fluid contact line. Journal of Colloid and Interface Science. 1971; 35: 85-101

Dussan V., EB., Davis SH. On the motion of a fluid-fluid interface along a solid surface. Journal of Fluid Mechanics. 1974; 65: 71-95

hi:

must we give the contact angle during the numerical simulation?

regards

That's the best way to do it. Then you have to decided whether the contact angle is static or dynamic. Static is more stable, but dynamic is more realistic. Depends on your application.

Thank you very much is the contact angle a constant?

That's what we mean by static and dynamic. A static contact angle is constant, but for a moving contact line it is physically unrealistic, although this might not be significant (depending on application). A dynamic contact angle is where theta varies, which is more realistic, but is MUCH more expensive computationally. Factors that can cause changes in contact angle are local velocity vector, surface shape/energy/cleanliness. Concentration, temperature and electric fields are other factors. Enjoy!

What do you exactly mean by computationally expensive? I'm working on pretty much the same stuff and I don't know if the static and dynamic contact angle implementations are very different. As long as you calculate the velocity of the contact line, using a dynamic contact angle model you should be able to evaluate the dynamic contact angle.

Cheers,

Shahriar