Experimental Investigation of the Effects of Pipe Material on the Leak Head-Discharge Relationship

Torricelli’s formula is often used to define the dependence of the leak outflow on the flow conditions inside the pipe and on the leak characteristics. Some tests carried out at the Water Engineering Laboratory of the University of Perugia, Italy, show that differences in the leak head-discharge relationships may arise even when the same leak is machined in pipes with the same inner diameter but different thickness and material. These data can still be explained by Torricelli’s formula if the possible variation of the leak area because of the head is considered. When the pipe material behaves in a linear and elastic fashion, the leak area variation with the head is linear, whereas other formulations are needed when elastoplastic or viscoelastic materials are used. As a consequence, this effect can produce different leak head-discharge relationships, depending on the constitutive law and behavior of the pipe material.