296 



HYDRAULICS AND ITS APPLICATIONS 



Rational Formula. 



From analogy with pipe flow it would appear probable that a formula 

 of the type 



flv n _Jv^ 



&'" 



where, as in the case of a pipe, n is in general less than 2, would most 

 nearly represent tbe law of channel flow. 



Claxton Fidler 1 has determined the values of /, n, and x from many 

 experimental results of Darcy, Bazin, Smith, Stearns, and other observers, 

 and the following table is abridged from values given by him : 



While further investigation may slightly alter these values, it is 

 extremely probable that the final solution of the problem of flow in 

 regular channels will be found in this type of formula. 



The pipe flow formula of Thrupp 



C n r" I 



where m is the hydraulic mean depth is also applicable to channel flow, 

 the following being the values of the quantities C n , n, and x. When m 

 I 



is small, x + a V 1 should be substituted for x. 



in 



1 Fidler, "Calculations in Hydraulic Engineering," Part II. (Longmans & Co.), 1902. 



