374 



HYDRAULICS AND ITS APPLICATIONS 



1 per cent, in each case. The reduction of efficiency at high as com- 

 pared with low velocities, is here to be accounted for by the interference 

 of the descending stream with the ascending jet. 



One interesting difference is to be noted between the behaviour of a 

 steady jet and of an unsteady (sinuous) jet on impact. The former 

 invariably impinges without any splashing. The latter, on the other hand, 



FIG. 167. 



is always accompanied by considerable splash. With a steady jet there 

 appears to be no formation of deadwater at the central point of impact, 

 such as is indicated in black in the sketches in Figs. 165 and 166. 



ART. 106. DISTRIBUTION OF PRESSURE OVER PLATE AT IMPACT. 



In general, this is unimportant, the total pressure only being needed. 

 Owing to the curvature of the stream in the neighbourhood of the 

 plate (Fig. 167), and to the centrifugal force caused thereby, the pressure 



