Water flows through a convergent mouthpiece of diameter 4 cm at convergence under a head of 3 metres. If the maximum vacuum pressure is 9 metres of water, the maximum diameter of divergence, to aviod separation of flow, is

Concept:

Mouthpiece:

A mouthpiece is an attachment in the form of a short length of the tube or pipe.

It is two or three times its diameter in length.

It is fitted to the tank containing fluid, through which liquid is discharged.

Classification of mouthpiece

1.According to the position of the mouthpiece

External mouthpiece: If the pipe projects outward from the wall of the reservoir, then it is called external mouthpiece.
Internal mouthpiece: If the pipe projects inside the tank (i.e. fixed internally), then it is called internal mouthpiece. The internal mouthpiece is also called Borda’s mouthpiece or reentrant mouthpiece.