304 
The pressure at P is 
Pi=Nor FCO Shi cnE 
veae is c <ite 
1 2 ox for to t t 
Sfhayes 2 cele 
= pee ei ae fort. Zt 
Pp Po 40 ——$——$——_=- 1 
2, Curvilinear Charges 
Case 1 Circular arc of charge, P at the centre of the circle. 
This case is shown in Figure 2(a). Using the same notation ag before, it is seen that 
<2 
ars 
ly FG 
Dee eR (t - t,) font She ty 
In this Case the equation for the pressure at P may be integrated directly to give 
p= 70 Sh 
a) a p= kit = +4) } LI 
mre 
= k —k(t = < 
P= pyc, ane k(t = to) Cs 
pS a 
kr * 
Case 2. Charge forming part of an equiangular spiral, P at the centre of the spiral. 
This example, given in Figure 2(b) is that for which all the elements start to be 
effective at p at the same instant. 1f S be the length along the charge from the point of 
detonation 0 to some point Q and pgQ=r 
s Y, r 
Hy 
and the charge is thus part of an equiangular spiral. 
Putting FS equal to the distance from P to the point of detonation, 
The pressure at Pp, after integration has been performed is 
P= ccevee 
