Influence of Manning’ Roughness Coefficient and Absolute Roughness in Velocity Calculation

The recommended calculation relations for flow and velocity determination in water supply and sewage systems are different and include parameters taken from tables or catalogs. The results obtained should be the same, regardless of the relations are follow, but applying the two relations for the same network resulted in different values of flows and velocitys. From the analysis of the relations obtained differences are derived from the values adopted from tables, for both the roughness coefficient n and the absolute roughness k. From the analysis effected, values obtine is a justification of the recommendations of the specialists.