PIPE FLOW 



CLEANED CAST IRON. (From Unwin.) 



209 



OLD, LIGHTLY TUBERCULATED CAST IRON. (From Tutton and Unwin.) 



Velocity, 



Diameter (inches). 



A series of experiments by Freeman l on the flow through fire hose, 

 give the following mean values of /, at velocities ranging from 10 to 30 

 feet per second. 



Unlined linen hose . . / = '0084 



Smooth rubber lined hose . / = '0044 



It is probable that at such velocities as are common in practice, viz., 

 ibout 100 feet per second, these values would become about '0080 for the 

 unlined, and *0040 for the rubber-lined hose. 



ART. 65. 



Since the velocity in a pipe is inversely proportional to x/J^an error in 

 .e assumed value of/ will only lead to approximately half the percentage 

 ?rror in v, and hence in the calculated discharge. Still, since the 

 physical condition of a pipe surface, and any deviation from straightness 



; Transactions American Society Civil Engineers," 1889, p. 303. 



H.A, 



