For external mouthpiece, absolute pressure head at vena-contracta is given as
(where Ha is the atmospheric pressure head and H is the height of liquid surface above the centre of the mouthpiece)
1
Ha - 0.89H
2
Ha + 0.33H
3
Ha + 0.95H
4
Ha - H
For external mouthpiece, absolute pressure head at vena-contracta is given as
(where Ha is the atmospheric pressure head and H is the height of liquid surface above the centre of the mouthpiece)