Partially Full Pipe Flow Calculations with Spreadsheets

by Harlan H. Bengtson

The Manning equation is used for a wide variety of uniform open channel flow calculations, including gravity flow in pipes, the topic of this book. Gravity flow occurs in pipes for partially full flow, up to and including full pipe flow, as long as the pipe isn’t pressurized. Equations for calculating area, wetted perimeter and hydraulic radius for partially full pipe flow are included in this book along with a brief review of the Manning equation and discussion of its use to calculate a) the flow rate in a given pipe (diameter, slope, & Manning roughness) at a specified depth of flow, b) the required diameter for a specified flow rate at a target percent full in a given pipe, and c) the normal depth (depth of flow) for a specified flow rate in a given pipe. This includes presentation and discussion of the equations for the calculations, example calculations, and spreadsheets to facilitate the calculations.

37 pages, Kindle Edition

First published February 18, 2012