Correct Answer - Option 4 : V
act. / V
th
Explanation:
Coefficient of Velocity:
(i) It is defined as the ratio between the actual velocity of jet at vena-contracta and the theoretical velocity of jet.
(ii) If V is the actual velocity of jet at vena-contracta then,
\({C_v} = \frac{{{V_{act}}}}{{{V_{th}}}}\)
(iii) The difference between the theoretical and the actual velocites of the jet at vena-contracta is mainly due to friction at the orifice. For sharp edged orifice, friction is considerably less.
(iv) The value of Cv varies form 0.95 to 0.99
