Understanding droplets aerodynamics and collision efficiency in fluid flow is crucial in various applications, including environmental science, industrial processes, and respiratory health studies. This research aims to numerically characterize interception-based deposition of finely divided liquid droplets—like in a fog—on a cylindrical fiber in a cross-flow. The solver is specifically designed to simulate the behavior of liquid droplets within the Lagrangian Particle Tracking (LPT) framework, and it has been implemented in OpenFOAM. The paper presents a rigorous validation study of the modified solver dedicated to investigating droplet behavior within fluid flow. A thorough validation has been conducted using established experimental data to assess the solver's accuracy and reliability. Additionally, the study explores the influence of Stokes number on particle flow, providing valuable insights into droplet collision with surfaces. The findings highlight the significance of the solver in predicting droplet–surface interactions and its potential applications in diverse fields. The validated solver holds promising potential for computing the performance of fog harvesting meshes and filters that are routinely deployed in environmental studies, industrial processes, and respiratory health research.