Optimizing coating processes can be difficult to model due to small scale of fluid motion and the influence of effects such as wall adhesion and surface tension. FLOW-3D provides a convenient way to analyze these processes without having to resort to costly laboratory experiments. FLOW-3D‘s models simulate surface tension gradients due to temperature variations, heat transfer, vaporization, condensation, solute transport and density-driven flows.

This FLOW-3D simulation of a forward roll coating process captures a ribbing defect due to a high capillary number. The model incorporates the effects of surface tension and viscosity as the backing rollers draw the fluid through a 400 micron nip. The simulation is based on research described in the paper ‘Ribbing instability in rigid and deformable forward roll coating flows’ presented in the Korea-Australia Rheology Journal Vol. 22. The accurate prediction of the onset of ribbing allows for researchers to identify optimal process parameters to avoid defects.