444 
The decrease of the energy flux with increasing distance 
from the charge allows us to give a physical interpretation to the 
qquantity x, which justifies its designation as the dissipation 
parameter. We shall in fact show that, although we have neglected 
dissipation terms in the equation of motion behind the shock front, 
our theory implicitly takes into account energy dissipation at the 
shock front and does so in the correct way. Differentiation of 
Eq. 6.15 and use of Eq. 6.2 yields 
SE be as ee (6.16) 
b, = (44,/R) be 
The rate of dissipation of Ep at the shock front is therefore pro- 
portional to Pe, the coefficient of O in the shockefront velocity, 
= (itso) « It can also be shown that for shock waves of low 
intensity, the parameter f- determines the entropy increment AS 
experienced by unit mass of water in passing through a shock front 
of peak pressure Poe 4 
ba [oe 
AS = ne lloge Sona 
. z 6. 
ly Bite J a+ ua ee x | vege 
6 o dpe F 
where v is the specific volume of water. Thus we may write, 
te a 
WaZs “ase te (6.18) 
6 60 
As the shock front advances a distance dR, the water in a volume 
57 
