Local dissipation limits the dynamics of impacting droplets on smooth and rough substrates

Abstract

A droplet that impacts onto a solid substrate deforms in a complex dynamics. To extract the principal mechanisms that dominate this dynamics, we deploy numerical simulations based on the phase field method. Direct comparison with experiments suggests that a dissipation local to the contact line limits the droplet spreading dynamics and its scaled maximum spreading radius βmax. By assuming linear response through a drag force at the contact line, our simulations rationalize experimental observations for droplet impact on both smooth and rough substrates, measured through a single contact line friction parameter μf . Moreover, our analysis shows that dissipation at the contact line can limit the dynamics and we describe βmax by the scaling law βmax ∼ (Reμl/μf ) 1/2 that is a function of the droplet viscosity (μl) and its Reynolds number (Re). This research was originally published in Physical Review E. © 2017 American Physical Society