ON TPIE FLOW OF WATER IN PIPES, CONDUITS, ETC. 143 



and others, many, indeed most, of which are found tabulated in the 1,200 

 examples given in Hering and Trautwine's translation of Kutter's Flow of 

 Water in Open Channels,* in determining the constants. 



Kuttei-'s formula, built empirically upon Darcy's and designed especially 

 for open channels, in which the conditions are rougher and more irregular 

 than for pipes, is the only one of wide and general scope in which V is 

 given in terms of fl", L, and r, which is employed by the profession with 

 more or less acceptable favor. Kutter's formula has not sufficient flexibility, 

 being constructed with only one variable parameter, a coefficient of rough- 

 ness known as n. The available data for the construction of such a formula 

 at the present day far exceeds that at Kutter's command, and it appears 

 that a more serviceable one can now be designed. 



13. Taking the value of m as given in (20) as a basis for such a design 

 and using the general class of "clean pipes" as a preliminary test, the 

 following solutions of the constants have been worked out and studied by the 

 writer. 



.015+ •°«°^ 



VD 



1 + .087 + \/2D 



„ , -0002 

 .016+-^ 



.0002 



.014 + 



VD 



1.5+ .Q8V + iD 

 .0002 



.015 



VD 



1 + .087 + 1.2Z?y3 

 .0002 



.016+- 



VD 



.00032 



.01548 



VD 



l + ^^{oV+^2D 



(35) 



(36) 

 (37) 

 (38) 

 (39) 

 (40) 



*We shall make such frequent reference to this book that we shall signify it in 

 the future by H. & T. In like manner we refer to Turneaure and Russell's book as 

 T. & B. 



