ABSTRACT
This chapter provides an empirical relationship for the coefficient of energy loss for tangential helicoidal-ramp inlets is developed from head-discharge measurements when the inflow pipe is flowing full. The energy loss coefficient in the closed-conduit flow regime was found to decrease exponentially with the ratio of the hydraulic diameter of the ramp to the diameter of the inflow pipe. Due to rapid growth and urbanization of most of the major cities in the world, the capacities of their wastewater systems often are no longer adequate to handle the large volumes of wastewater discharged from houses and factories and from surface runoff during large storms. A flow-straightener section was installed at the upstream end of the inflow pipe to avoid secondary velocities and insure a smooth flow in the inflow pipe. A vortex-flow inlet to dropstructures, called the tangential helicoidal-ramp inlet, was developed and tested in a laboratory study.
