the formula commonly given for the discharge of rectangular orifices.
The coefficient c is not, however, simply the coefficient of
contraction, the value of which is
b(h2 - h1)/B(H2 - H1),
and not that given in (7). It cannot be assumed, therefore, that c in
equation (8) is constant, and in fact it is found to vary for
different values of B/H2 and B/H1, and must be ascertained
experimentally.
_Relation between the Expressions (5) and (8)._--For a rectangular
orifice the area of the orifice is [omega] = B(H2 - H1), and the
depth measured to its centre is ½(H2 + H1). Putting these values in
(5),
Q1 = cB(H2 - H1) [root]{g(H2 + H1)}.