1570 
occurring at(R,, @) then the total pressure must equal the cavitation 
pressure: 
Aled pli) -P(E54) « pe 
(148) 
W; is defined by this equation in the region of cavitation 
and by assumption (c) elsewhere. To make (148)explicit for calculation 
using empirical data, we note from the geometry of Figure 18c that 
X = R, - Rp 
(149) 
Ro = R* + 4d°-4dR, cos 6 
If p is the atmospheric pressure and H is the vertical 
hydrostatic pressure gradient ,then 
p, (Ry,9) =p + H (Ri cose -d) (150) 
Letting §(t) be the fraction of the peak pressure which 
obtains at reduced time T we can write 
peo) Mrz 9) 
The function £( t ) is obtained from a composite curve of 
(151) 
pressure versus reduced time at some particular reduced. distance?3 
and the function pio) from a similarity ee 
The reduced time t is related to the distance xX » and the 
sound velocity C by an empirical relation!+ valid for INT or 
pentolite 
(x 
x 
ara (152) 
= . Y_4\ -0.18 
acto cw ) 
yele 
