A note on the modelling of lubrication forces in unresolved simulations

Lubrication forces play a major role in the behaviour of fluid–solid systems, where they affect the collisions between particles. Current implementations of lubrication forces in unresolved simulations often suffer from shortcomings, such as neglecting parts of the physics or relying on arbitrarily defined parameters. In this short communication, we propose a novel implementation, rigorously defined based on physical and numerical factors. Both particle roughness and deformation are considered, and the model accuracy is demonstrated through comparison with experimental results. [Display omitted] •A rigorously-defined lubrication force model for unresolved simulations is proposed.•Surface roughness and particle deformation are considered.•Numerical stability is ensured by a continuous force formulation.•Good correspondence with experimental data is demonstrated.