Numerical Prediction of Water Film Thickness on Pavement during Rainfall

The purpose of this study is to develop a finite volume model to predict the water film thickness on a road pavement during rainfall. Raindrops are treated as dispersed spherical particles in a continuous gas phase of air. The numerical simulation analysis is performed using the Eulerian-Lagrangian approach. The discrete raindrops are represented in a Lagrangian frame of reference. An Euler thin film model is employed to study the flow behavior of the thin water film on the pavement surface analyzed. The analysis demonstrates that water film thickness is affected only by rainfall intensity and not by raindrop diameter. Currently no theoretical model is able to analyze the effect of pavement macrotexture on water film thickness. The proposed model provides a solution to overcome this limitation through the use of square grid grooves. The validity and accuracy of the simulation model was verified against experimentally measured water film thicknesses.