IMPACT OF JETS 



375 



increases along the radius of curvature towards the surface of the 

 plate and the centre of the jet, the velocity suffering a corresponding 

 diminution. 

 Assuming no loss of energy before impact, the energy per Ib. of water 



v* 

 will be a = h ft- Ibs., where, in the case of a vertical jet, h is the height 



A 9 



of the free surface of the supply reservoir above the plate. Thus, at the 

 centre of the jet at the plate where the velocity is zero, the pressure 



W v 2 

 intensity will have its maximum value W h = , - Ibs. per square foot. 



*9 



From this point the pressure intensity falls off radially as indicated in 

 the figure, the pressure curve being approximately as shown. 



Experiments show that the pressure at the centre of the jet is 



v 2 

 practically the same as (slightly less than) that corresponding to s feet 



9 



of water. 



The following table, taken in abstract from the Eoorkee Papers on 

 Indian Engineering (" Proc. Inst. C.E.," vol. 60, p. 436), shows the 

 pressure exerted at different radii by a vertical jet 1J" diameter, when 

 impinging normally on a fixed plate. 



