Analytical and numerical validation of a plate-plate tribometer for measuring wall slip

Data set and case setup for verification and validation numerical studies of the simplified analytical model that predicts the slip length. The plate tribometer is specially designed to measure viscosity and slip length simultaneously for lubrication gaps in the range of approximately 10 micrometres at relevant temperatures and surface roughness. We investigate the inlet effect of the flow on the results by varying the inner radius of the fluid inlet pipe. The outcomes of numerical simulations suggest that variations in the diameter of this inner radius have minimal impact on the results. Specifically, any alterations in the velocity profile near the inlet, brought about by changes in the diameter, quickly revert to the profile predicted by the analytical model. The main conclusion drawn from this study is the validation of the Navier-Slip boundary condition as an effective model for technical surface roughness in CFD simulations and the negligible influence of the inlet effect on the fluid dynamics between the tribometer's plates.