[JoaoMiranda]

Usually in a VOF method the contact angle is introduced in the simulation in the calculation of the curvature. The curvature near the boundary is determined based the vector normal to the surface. The vector normal to the surface is calculated from the contact angle.



The vector normal to the surface, n=(nx,ny,nz) is related to the angle by:

ny/SQRT(nx^2+nz^2)=cot(theta)


According to the following paper:


Chen Fang, Carlos Hidrovo, Fu-min Wang, John Eaton, Kenneth Goodson, 3-D numerical simulation of contact angle hysteresis for microscale two phase flow, International Journal of Multiphase Flow, Volume 34, Issue 7, July 2008, Pages 690-705


the calculation of the contact angle becomes complicated in corners, where two angles exist. The calculation of the vector normal do the surface becomes impossible for angles smaller than 45 degrees.


The vector n=(1,ny,nz) is related to the angle by:


ny=cos(theta1)/(1-cos(theta1)^2-cos(theta2)^2)


nz=cos(theta2)/(1-cos(theta1)^2-cos(theta2)^2)


These equation only work for cos(theta1)^2+cos(theta2)^2>1


How are these calculations handled in InterFoam? Specifically, how are contact angles handled in corners?