Davis and English 



I 'eoiA 



— -£. 



DRIVE SHAFT 



DOWNSTREAM 

 FAIRING CONE 



INNER BRASS 

 TUBE 



WAKE SIMULATOR 



Fig. A-1 - Diagrammatic arrangement of fully 

 cavitating screw with wake simulator 



is sketched in Fig. A-1, and two sample sets of pressure measurements are 

 given below. 



(i) J = 0.80; a = 0.35 



Pressure tap 

 position 



Absolute pressure 

 lbf/ft2 ^ 



(ii) J = 0.3; a = 2.7 



Pressure tap 

 position 



Absolute pressure 

 Ibf/ft^ -^ 



Tunnel water speed =27.0 ft/sec 

 Screw rate of rotation = 40.5 rps 

 Vapour pressure = 44 Ibf/ft^ 



B 



(Atmospheric) (Upstream) 

 (static) 



D 



2120 



314 



129 151 178 169 



Tunnel water speed = 10.5 ft/sec 

 Screw rate of rotation = 42.0 rps 

 Vapour pressure = 47 Ibf/ft^ 



B 



(Atmospheric) (Upstream) 

 (static ) 



D 



2120 



339 



48 79 129 125 



In the first case the pressure at F, which was used in the pull correction, 

 was considerably different from the upstream static pressure at B which would 

 have been used in making the pull correction in uniform flow. For these results 



1014 



