A far-field boundary condition for measuring drag force on micro/nano particles

Predicting the flow around airborne particles smaller than 1 µm is challenging because the flow is rarefied and occurs at very low Reynolds numbers, requiring the Boltzmann equation to be solved using the computationally expensive Direct Simulation Monte Carlo (DSMC) method. In this work, we propose a boundary condition based on the far-field solution of the Stokes equations, allowing accurate drag force predictions using much smaller DSMC domains. This reduces computational cost by up to three orders of magnitude and enables the first tractable calculations for arbitrary-shaped 3D particles in the transition regime. This folder contains the data for reproducing the figures in the article mentioned above, including the non-dimensionalised drag forces and percentage error for two shaped particles with increasing domain size, using the conventional approach and our Stokeslet-corrected boundary condition.