A Mathematical Computation of the Transition Flows between Pressurized and Non-Pressurized Conditions in Pipes

The flow condition in pipe has to be ascertained hydraulically in order to attain effective outlet for stormwater through sewers in a sewerage network in urban areas. The transition flows between pressurized and non-pressurized conditions are calculated under two boundary types, namely, inundation of the basin and when water level at the downstream end rising. To calculate the transition flows, two models are used that is, the slot model and a new proposed model which we name it the exact model. Slot model can deal with the pressurized flow as well as the non-pressurized one by assuming the slot on pipe. The exact model describes the flow in the pipe without considering the hypothetical slot. Obtained results from these models show that the exact model can be used transient flow in pipes and the occurrence of the transition flows which influences on the drainage performance. Thus, plans for sewer systems are approached, considering the total management in the basins