Abstract
Authors have already investigated characteristics of the energy loss in a three-way circular drop manhole and formulation of the energy loss coefficients in consideration of six dimensionless variables for structural elements of pipes and manhole, and hydraulic parameters. However, the calculation formula of the energy loss for drops between two opposed inflow pipes and an outlet pipe has not existed yet. In this study, for a three-way circular manhole with drops between two opposed inflow pipes and an outlet pipe, energy loss is examined experimentally. From the experimental results on the energy loss at the manhole with drop gaps between the opposed inflow pipes, the increase of the pressure head in an inflow pipe brings head loss depending on collision conditions of water flow into the manhole from another opposed inflow pipe. These experimental results brought a more versatile formula than the proposed formula by authors before.
