LARGE ORIFICES 



133 



Ordinary lock sluices ..... 

 Small regulator openings with shallow water 

 Regulator openings up to 6 feet wide with r 



in the piers ....... J 



Ditto between 6 feet and 13 feet wide 



Ditto above 13 feet wide 



Regulator openings up to 6 feet wide with straight^ 



and continuous piers .... [ 



Ditto between 6 feet and 13 feet wide 

 Ditto above 13 feet wide 



C = 



62 

 57 



62 



72 



82 



72 



82 

 92 



A series of experiments 1 on a submerged orifice 4 feet square through 

 a wooden bulkhead 3*75 inches thick, with various forms of entry, gave 

 the following values of C : 



In every case the minimum value of C was obtained with a mean 

 velocity of flow ranging from 1*9 to 2'3 feet per sec., the velocities of flow 

 ranging from approximately I'O to 4 '0 feet per sec. 



The experiments were extended by the addition of tubes of lengths 

 62, 1-25, 2*50, 5'0, lO'O, and 14'0 feet on the discharge side of the 

 orifices, and the curves of Fig. 72 denote to what extent these affected 

 the discharge. 



For the tubes having square corners at the entrance, the coefficient of 

 discharge increases at first almost directly as the length of tube increases, 

 then at a gradually decreasing rate until the length " L " of the tube 

 becomes between 3 and 3*5 times the side of the square. For lengths 



1 " Bulletin of the University of Wisconsin," No. 216. Engineering Series, vol. 4, No. 4. 



