2.4 

 2.2 



O 



I- 



2: 1.0 



0.8 I— 



0.6 



0.4 



1 



1 I 



R^ = 5(10)^ ' ' 





I 





— 



o 

 O 



PARENT 

 TVC PMI 1 

 TVC PMI 2 







— 





D 



TVC PMI 2 WITH ROUGHNESS- 

 600 M, 12.7 mm STRIP 

 PRESSURE SIDE TIP 



o 







■~ 







HOLE CAVITATION PMI 1 / 



V 



"V 



— 





A 



HOLE CAVITATION PMI 2 i C 



17 



/S. <J^ 







V 



1 «5 



V* 







/\ 



/ 1 



r 



/v 





~~ 



\1 





f " 



^ 





^ \ 



1 



/ 



6 







\ \ 



1 / 



/> 



c 



:_ 







/ 



7 



/ 







V 



\ / / >6 



( 



/ 









\ / A/ 



I 



i 









nk Ls^ 



)V^ 





~ 



- 





w^^^y 



r 





- 



— 











- 



1 



1 L^ 











0.1 0.2 



LIFT COEFFICIENT C, 



Figure 31 - Tip Vortex Cavitation Inception as a Function of Lift 

 Coefficient — Passive Mass Injection Foil 



(excluding the channel area) 0.5 in. (0.013 m) inboard from the foil tip. As seen 

 in Figure 31, this configuration resulted in substantial improvement in TVC perform- 

 ance as compared to PMI 2 without roughness. 



The PMI data are also presented in Figure 32 to show the relative increase in 

 TVC inception speed over a range of C . The data trends are basically as discussed 

 above (for increasing C the PMI 1 becomes less effective, indicating an insufficient 

 mass flow into the vortex core, while the PMI 2 shows a steady increase in perform- 

 ance due to the larger mass flows associated with the larger channel) . PMI 2 is the 

 largest size channel which could be physically accommodated in the foil tip. 

 However, these trends indicate that TVC performance increases with increasing PMI 



44 



