NSWC/WOL TR 76-15 5 



Calculation of PNEG Above/Inside/Under Region of Cavitation 

 Let the depths, y and y , locate the top and bottom of the region 

 of cavitation. Let p =p.+PNEG be the absolute pressure under the 



Ado 1 



influence of cavitation, i.e., following arrival of the surface 

 reflected wave. For fish located above/inside/under the region of 

 cavitation, p, DC . is determined as follows: 



Ado 



Above: p AT3C , changes linearly with depth from PATM at 



Add 



the surface to PVAP at the top of the cavitation. 

 Inside: p, DC . = PVAP 



Ado 



Under: p ABg = PVAP + pg(y-y c ) 



where PVAP and p are the vapor pressure and density of water, and 

 g is the acceleration of gravity. Since 



PNEG = Pabs - Pi <C5) 



the corresponding equations for PNEG are (see Figure C2) 



-[PATM + pgy - PVAP]^— 0<y<y (C6a) 



Y t 



PNEG =) -[PATM + pgy - PVAP] y t <y£y (C6b) 



-[PATM + pgy - PVAP] y>y (C6c) 



C-4 



