UNCLASSIFIED 



(Block 10) 



I Program Element 62543N 

 i Task Area ZF 43-421-001 

 j Work Unit 1500-104 



! (Block 20 continued) 



Naval Ship Research and Development Center 24-inch cavitation tunnel, where 

 i the effects of the various concepts on both foil tip vortex cavitation in- 

 I ception and performance were established. These measurements were made at i. 



? r 



i Reynolds number R , based on root chord length, of approximately 5 x 10 . 



! Some of the more fundamental aspects of the tip vortex rollup process 

 i have been documented through the use of flow visualization techniques. The 

 results for the tip vortex cavitation delay concepts indicate substantial 

 increases in the tip vortex cavitation inception speed relative to the un- 

 altered tip; i.e., a 94 percent increase for the roughened tip, 38 percent 

 for the bulbous tip, and 54 percent and 33 percent for the active and 

 passive mass injected tips respectively. These results were obtained over 

 a wide range of foil angle of attack and with little or no measurable loss 

 in foil performance; i.e., no measurable lift decrease or drag increase. 



UNCLASSIFIED 



SECURITY CL AESlriCATIOiv! Cr THiS ?A< 



