  A mesh-dependent relation for the slip number in the Navier-slip with
friction boundary condition for computations of impinging droplets with sharp
interface methods is proposed. The relation is obtained as a function of
Reynolds number, Weber number and the mesh size. The proposed relation is
validated for several test cases by comparing the numerically obtained wetting
diameter with the experimental results. Further, the computationally obtained
maximum wetting diameter using the proposed slip relation is verified with the
theoretical predictions. The relative error between the computationally
obtained maximum wetting diameter and the theoretical predictions is less than
10 % for impinging droplet on a hydrophilic surface, and the error increases in
the case of hydrophobic surface.
