FLOW OF WATER THROUGH PIPES. 1 29 



nominator represents the resistance offered by the pipe 

 to the flow of water through it as determined by the 

 author of this formula. When the numerical values 

 found for e and c are substituted, the result is the veloc- 

 ity formula for falling bodies modified so that it will 

 apply to the velocity of water in pipes. 



There are formulas which are just as accurate and 

 possess the very desirable excellence of greater sim- 

 plicity in which g and h are combined with quantities 

 whose value has been determined by experiment. 

 Beardmore^s formula is one of these simple expressions: 



V = 100 VjRS, (3) 



where R = hydraulic mean depth 



area of waterway a 



~ wet perimeter ~ / ' 



^ . - , head in feet A 



o = sme of slope = , -, — r — = — = t . 



length of pipe / 



This formula written out in full is as follows : 



area head 



"^ I perimeter length of pipe' * ^^^ 



In this expression the constants g and coefficients 

 of friction are merged into one common constant, 100, 

 and the variable quantities are expressed in terms which 

 may always be determined for each particular pipe. 



The above are examples of reliable velocity formulas 

 made use of by engineers in computing the flow of water 

 through pipes of various kinds and sewers of various 

 descriptions when the head of water is known and the 

 pipes come within reasonable limits of perfection in 

 workmanship. The American unit is feet per second 



