Computational study of rivulets using Volume of Fluid

Licentiatavhandling, 2009

This thesis focuses on numerical methods of soiling and some multiphase concepts related to it. The Volume of Fluid method was tested in two different test cases and showed fairly good results. The first test case was a gravity driven rivulet on an inclined plate, where it was an inlet with a constant water velocity at the beginning of the plate. We tested three different grids and five different discretization schemes for the interface equation, and it was found that the sharpest and most accurate one was the Young scheme. The second was a wind driven rivulet on a flat plate. The experiment setup is a $20mm$ thick, $260x300mm^2$ plate with a 1mm circular water inlet centered on top of the plate. Ambient air flows on both sides of the plate. As the water is introduced, the ambient air will form a rivulet that travels towards the trailing edge of the plate. The rivulet breaks up at the trailing edge, forming droplets of sizes that depend on the flow rate and velocity of the ambient flow. The hole was moved 1 cm upstream of the edge to avoid the rivulet from breaking up on the plate. The results were good for the droplet size and velocity. The sharpest scheme did not converge at all, and thus the HRIC scheme was used instead of the Young scheme.