Numerical Study on Microdroplets Interaction with Solid Surfaces

Abstract

The presented study addresses the issue of deposition and splashing of microscopic droplets upon impact with a solid surface. It presents the results of numerical simulations using the commercial code ANSYS Fluent 2025R accelerated using a newly implemented multiphase VOF GPU solver. The simulations allowed us to study the whole process with both spatial and temporal resolution, which is currently on the edge of the experimental capabilities. The simulation results were in qualitative agreement with published experimental data and captured in detail the droplet deposition or formation of micro ligaments, and the subsequent separation of secondary microdroplets that propagate upon splashing into the surroundings. An important finding is the effect of high surface roughness on droplet impact. If the value of roughness is comparable to the droplet diameter, the dissipation of kinetic energy occurs, which shifts the limit of the transition to the splash regime to higher impact velocities compared to smooth surfaces. Another effect observed was the thickness of the liquid film on the rough surface. It was found that a liquid film with a thickness comparable to the surface roughness promotes splash formation, whereas a thicker film does not show this effect.

The presented study addresses the issue of deposition and splashing of microscopic droplets upon impact with a solid surface. It presents the results of numerical simulations using the commercial code ANSYS Fluent 2025R accelerated using a newly implemented multiphase VOF GPU solver. The simulations allowed us to study the whole process with both spatial and temporal resolution, which is currently on the edge of the experimental capabilities. The simulation results were in qualitative agreement with published experimental data and captured in detail the droplet deposition or formation of micro ligaments, and the subsequent separation of secondary microdroplets that propagate upon splashing into the surroundings. An important finding is the effect of high surface roughness on droplet impact. If the value of roughness is comparable to the droplet diameter, the dissipation of kinetic energy occurs, which shifts the limit of the transition to the splash regime to higher impact velocities compared to smooth surfaces. Another effect observed was the thickness of the liquid film on the rough surface. It was found that a liquid film with a thickness comparable to the surface roughness promotes splash formation, whereas a thicker film does not show this effect.