Computational Fluid Dynamics of Manhole Overflow Due to Storm-water Inflow

Abstract

In this study, the storm water overflow on manholes is numerically solved. To produce a real representation of storm overflow, the Navier-Stokes equations were used. Turbulence was modelled using the standard k-epsilon turbulence model together with the volume of fluid method for phase surface tracking. The open-source computational fluid dynamics (CFD) tool OpenFOAM 5.0 was used for solving the model while the visualization tool, paraview 5.4.0, was used for processing the solution data. The convergence test was performed at three different mesh sizes. The numerical solution established mesh independence by producing similar results at varied meshes sizes. The risen storm-water column inside the manhole exerts a non-uniform pressure on the manhole cover. The non-uniform pressure distribution leads to different uplifting forces at manhole cover areas. However, the global uplifting force remains constant as long as the storm water overflow is occurring on the manhole. The overflow intensity on the manhole is not the same, areas opposite to the outlet pipe provide the highest intensity of the leaking storm-water.