Investigations of drop impact on dry walls with a lattice-Boltzmann model

In this work, axisymmetric computations of drop impingement on dry walls are presented. The two-phase model employed is an axisymmetric lattice-Boltzmann model. Computations are performed in the parametric range of Weber number We of 7 to 8770, Ohnesorge number Oh of 0.02 to 0.137, and drop-wall equilibrium contact angle theta(eq) of 35 degrees to 150 degrees. Deposition and rebound outcomes are reported. In deposition, the different stages of drop evolution including spread, recoil and equilibration are reproduced and studied. Comparisons made with experimentally reported data of temporal evolution of the spread factor and the dynamic evolution of the contact angle show good agreement. Rebound is observed on non-wetting surfaces. The transition between deposition and rebound is shown to be influenced by the impact We, Oh, and advancing and receding static contact angles. Apart from impingement outcomes, the influence of We and Oh on the dynamic contact angle is investigated. (c) 2007 Elsevier Inc. All rights reserved.