An undamped oscillation model with two different contact angles for a spherical droplet impacting on solid surface

In order to further elucidate the dynamic theory of droplet oscillating on solid surface, a new handling method of contact angle of the droplet during the process of the oscillation was founded, which is based on the spherical model. The influence of gravity on the contact angle and spreading radius was discussed. Thus, an equation between the spreading radius of the droplet and time flow was founded. The results of theoretical calculation were compared with smoothed numerical results.