THE FLOW OF WATER IN WOOD-STAVE PIPE, 3 



the flow) were in the main correct. But a thorough, study of the flow 

 of water in pipes, and more particularly wood-stave and concrete 

 pipes, has convinced nim that Kutter's formula is not best adapted 

 to flow through pipes running full and under pressure. The work of 

 recent experimenters indicates that the exponential type of formula 

 is best adapted to such flow. Therefore the new formula is of the 

 exponential type. 



Much uncertainty has existed in the minds of hydrauHc engineers 

 during the past 30 years with regard to the carrying capacities of 

 stave pipe. If the new formula helps to clear up former uncertain- 

 ties and give to those engaged in the design and operation of stave 

 pipes a reliable guide by which to determiae flow through such con- 

 duits, it will have served its purpose. 



NOMENCLATURE. 



Unless otherwise noted, the various symbols used throughout 

 this pubhcation will have the following significance: 



d — ^The mean inside diameter of the pipe in inches. 



D — The mean inside diameter of the pipe in feet. 



r — ^The mean inside radius of the pipe, or ^D, in feet. 



Q — The mean discharge of the pipe, during the test, in second-feet. 



A — The mean area of the pipe bore, in square feet, =TrT^. 



V — The mean velocity of the water, during the test, in feet per second. 



L — ^The length of reach tested, in feet. 



hf — ^The head of elevation lost in overcoming internal resistances within a fairly 



TTT 



straight pipe of uniform size, in feet,=^jYvj7r- 



H — The above loss (termed friction loss) per 1,000 linear feet of pipe, = — =? — ^• 



hy — The head of elevation lost in creating the mean velocity, V, in feet. Called 



velocity head. 

 \^ — ^The velocity head recovered as the velocity is reduced at the pipe outlet, in feet. 

 he — ^The head of elevation lost at a pipe intake due to impact and entrance resistances, 



in feet, here called entry head. 

 P — ^The wetted perimeter; in a pipe under pressure, the inside circumference, =7rD 



or 27rr, in feet. 



A D 



E. — ^The hydraulic radius, = p; in a circular pipe, under pressure, =-27' 



s — ^The hydraulic grade or slope, in feet per foot of length of a pipe of uniform size, 



~L 

 n — ^The coeflS.cient of retardation in Kutter's formula. 

 C — The coefficient of retardation in Chezy's formula. 



Cw — ^The coefficient of retardation in the WilUams-Hazen formula. Not to be con- 

 fused with C in the Chezy formula, 

 f — ^The coefficient of retardation in the Weisbach fonnula. (This formula is variously 



known as Weisbach's, Weston's, Darcy's, and Chezy's.) (See p. 6.) 

 H=m v. — The general equation for the flow of water in a pipe, in which m is the 

 intercept on the vertical axis and z is the slope of the line, expressed as 

 the tangent of the angle between the line and the horizontal axis. (See 

 equation 17, p. 49.) 



