96 HYDRAULICS. 



SOLUTION. 12x64.33=771.96, the square root of which 

 is 27.780 feet per second. Ans. 



To find the head, the velocity being given. 



RULE. Square the velocity and divide it by 64.33, and 

 the quotient will be the head in feet. 



EXAMPLE. What is the head of water that projects a 

 stream 27.780 feet per second ? 



SOLUTION. 27.780 2 =771.96-7-64.33=12 feet. Ans. 



NOTE. In the above results no allowance is made for 

 friction, which should be made in order to ascertain the 

 practical results. The friction of water passing out of 

 orifices, and not through pipes, sluices, or sewers, is, how- 

 ever, very small. 



To find the quantity of water that will issue from an 

 opening, the dimensions of the opening and the head being 

 given. 



RULE. Find the velocity of the jet or stream by the 

 foregoing rule, and multiply it by the area of the orifice 

 in feet, and the product will be the number of cubic feet 

 per second the orifice will discharge. 



EXAMPLE. How much water will an orifice of an area 

 of 2 square feet discharge per second under a head of 12 

 feet? 



SOLUTION. 12x64.33=771.96, the square root of which 

 is 27.780 feet velocity; then, 27.780x2 feet, 

 cubic feet per second. Ans. 



