Dear All
I am trying to calculate discharge from a spillway with breast wall. The formula
given by IS 6934 assumes the end contractions on account of piers and abutments
. But most of the text books which give the discharge for small orifice do not
account for the contraction (as it is already taken care for in Cd) . Small
orifice is the one where head over centre (Hc) > (D) Height of orifice.
If we proceed with IS code formula, it gives the erratic nature of rating curve
as Le, decreases with increase in head and hence discharge decreases (Though Hc
is increasing.)

Can anybody throw some light over how to proceed with the calculations?

Thanking all of you in advance

Regards
Kaustubh

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