1558 
13.4 If we assume that the rise of the front is sufficiently 
abrupt to justify our continued use of the Rankine-Hugoniot 
conditions, we may calculate the irreversible shock loss by use 
of equation (36) of Navord 406+%, which after some manipulation 
leads to the form: 
0. 39 
4 0.39 Y, 
6 w i, 
Aé, = 3.15 (Io wi ) —_— e , (140) 
Values of A Ee calculated by means of equation (140) are also 
given in Table III, together with the sum Ae. oe Le, 
where AE, is the average of the upper and lower limits of 
the viscous dissipation. This sum is compared with the quantity 
QE as calculated over the same interval of w/3/m from the 
energy curve of Figure 15 extrapolated to W/3/R = 0.00022. 
The aneerualnty in this calculation is large since 4E is a 
small residual of a subtraction of large numbers. 
Another rough estimate of AVE may be obtained by use 
of the peak pressure and time constant similarity curves and 
calculating Z (Bae G /2 r C), on the assumption that the pressure 
wave igs purely exponential from t = o to 00. The empirical 
equation for the time constant as obtained from Figure 2 of Nav 
Ord 424° is approximately: 
w/3  .0.22 
O = 58 (1075) w/73 (—) sec. (141) 
R 
Then, making use of equations (104) and (141), 
LE = at = 4.36 (108) wi"? ei (in. /b.) (142) 
Q 
- 62. 
