373 



where p is the peak pressure in p.s.i., 6 the time constant in msec, 

 R the distance in feet, and W the charge weight in lbs.; and (3) calcu- 

 lated from the parabolic treatment using the empirical pressure-time 

 curves above. In figure 1 curves corresponding to the third set of cal- 

 culated values in table I are compared with the experimental values. 



In table II we present comparisons of calculated and experi- 

 mental values of the maximum diaphragm deflections for the case of small 

 charges of loose tetryl, density 0,97 ± 0,05. Two sets of calculated 

 values are given: (1) calculated from the two-mode Bessel-ftinction treat- 

 ment, and (2) calc\iLated from the parabolic treatment. All of the calcu- 

 lated values are based upon the theoretical pressure-time curves^/ for 

 tetryl, density 1.00, Cases for which cavitation is believed to occur by 

 the criterion of Part II, Section 2, are marked by asterisks at the left 

 of the table; however, it is believed that cavitation is not well developed 

 and that the theories of Parts III and IV may roughly apply. In figure 2 

 curves corresponding to the second set of calculated values in table II are 

 compared with the experimental values. 



The calculated values of the deflection, except those calculated 

 fi?om the parabolic treatment for small tetryl charges, are considerably 

 higher than the experimental values. For large charges of case TNT (table 

 I and figure 1), the deflections calculated from the two-mode Bessel- func- 

 tion treatment using theoretical pressure-time curves are on the average 

 31^ higher than the experimental deflections, those calculated from the 

 same treatment using empirical pressure-time curves are 12^ higher, and 

 finally those calculated from the parabolic treatment using the same empir- 

 ical pressure- time curves are 5.2^ higher. For small charges of loose 



58 



