1431 
II. BASIC THEORETICAL RELATIONS FOR 
SHOCKWAVES IN WATER 
Prior to formulating any discussion concerning shockwaves 
in water, the relation between pressure, temperature, and 
specific volume must be known. This relation is usually des- 
cribed by the equation of state which, in the case of water, is 
difficult to derive. Usually an approximate equation of state 
is applied, such as the one given by J. von Neumann in Ref. 1. 
For extremely high pressures an equation of state was derived 
theoretically for water by G. Burkhardt (Ref. 2) and correlated 
to the measurements of Bridgman. However, it is often possible 
to use initially the experimental data as presented, for in- 
stance, in Ref. 3 and derive the relation mentioned above. 
In Ref. 4 the following equation of state is used to de- 
rive the speed D of a shockwave in water: 
vevi(i+at-ki +fpar -tr*spe*) (1) 
The values for “~, k, ? ’ {, and Ph are given in Ref. 4 and have 
been derived from the original measurements of Bridgman. 7 is 
the difference between the pressure in the medium behind and in 
front of the shockwave, © the corresponding difference in temper- 
ature. It was found 
D ei a = a, C/+u7) (2) 
