MODELING OF CONTACT ANGLES AND WETTING EFFECTS WITH PARTICLE METHODS

The physics of fluid–fluid–solid contact line dynamics and wetting behaviors are closely related to the inter-particle and intra-molecular hydrodynamic interactions of the concerned multiple phase system. Investigation of surface tension, contact angle, and wetting behavior using molecular dynamics (MD) is practical only on extremely small time scales (nanoseconds) and length scales (nanometers) even if the most advanced high-performance computers are used. In this article we introduce two particle methods, which are smoothed particle hydrodynamics (SPH) and dissipative particle dynamics (DPD), for multiphase fluid motion on continuum scale and meso-scale (between the molecular and continuum scales). In both methods, the interaction of fluid particles and solid particles can be used to study fluid–fluid–solid contact line dynamics with different wetting behaviors. The interaction strengths between fluid particles and between fluid and wall particles are closely related to the wetting behavior and the contact angles. The effectiveness of SPH and DPD in modeling contact line dynamics and wetting behavior has been demonstrated by a number of numerical examples that show the complexity of different multiphase flow behaviors.