ax ter ▁state . ▁The ▁most ▁stable ▁contact ▁angle ▁can ▁be ▁connected ▁to ▁the ▁Young ▁contact ▁angle . ▁The ▁contact ▁angles ▁calculated ▁from ▁the ▁W enz el ▁and ▁Cass ie - B ax ter ▁equations ▁have ▁been ▁found ▁to ▁be ▁good ▁approxim ations ▁of ▁the ▁most ▁stable ▁contact ▁angles ▁with ▁real ▁surfaces . ▁ ▁Dynamic ▁contact ▁angles ▁For ▁liquid ▁moving ▁quickly ▁over ▁a ▁surface , ▁the ▁contact ▁angle ▁can ▁be ▁alter ed ▁from ▁its ▁value ▁at ▁rest . ▁The ▁adv ancing ▁contact ▁angle ▁will ▁increase ▁with ▁speed , ▁and ▁the ▁re ced ing ▁contact ▁angle ▁will ▁decrease . ▁The ▁dis cre pan cies ▁between ▁static ▁and ▁dynamic ▁contact ▁angles ▁are ▁closely ▁proportional ▁to ▁the ▁cap ill ary ▁number , ▁noted ▁ ▁. ▁ ▁Contact ▁angle ▁curv ature ▁On ▁the ▁basis ▁of ▁inter fa cial ▁energ ies , ▁the ▁profile ▁of ▁a ▁surface ▁dro ple t ▁or ▁a ▁liquid ▁bridge ▁between ▁two ▁surfaces ▁can ▁be ▁described ▁by ▁the ▁Young – L ap lace ▁equation . ▁This ▁equation ▁is ▁applicable ▁for ▁three - dimensional ▁axis ym metric ▁conditions ▁and ▁is ▁highly ▁non - linear . ▁This ▁is ▁due ▁to ▁the ▁mean ▁curv ature ▁term ▁which ▁includes ▁products ▁of ▁first - ▁and ▁second - order ▁derivatives ▁of ▁the ▁drop ▁shape ▁function ▁: ▁ ▁Sol ving ▁this ▁elli ptic ▁partial ▁differential ▁equation ▁that ▁gover ns ▁the ▁shape ▁of ▁a ▁three - dimensional ▁drop , ▁in ▁conj unction ▁with ▁appropriate ▁boundary ▁conditions , ▁is ▁complicated , ▁and ▁an ▁alternate ▁energy ▁minim ization ▁approach ▁to ▁this ▁is ▁generally ▁adopted