THREE-DIMENSIONAL NUMERICAL STUDY OF STACKED DROP MANHOLES

Abstract

Steep slopped urban areas require the use of drop manholes structures in order to achieve acceptable flow velocity inside the gravity network by reducing the slope of sewer pipes. Despite the wide usage of drop manholes structures there are no specific criteria that governs the height, and the cross section area of the drop manholes except for the concern of excessive aeration and corrosion, as this may lead to poor hydraulic conditions, and low energy dissipation efficiency. The dominant hydraulic properties of the drop manholes depend on the manhole geometry, and the generated flow regimes inside the manhole based on the inflow conditions, which governs the energy dissipation efficiency.