NSWC/WOL TR 76-155 



4 APPLICATIONS 



4 . 1 FISH-KILL CONTOURS 



Figure 4.1.1 shows the region of greater than 50% kill pre- 

 dicted for 18-cm long Spot in the vicinity of a 32 kilogram pentolite 

 explosion at 9 meter depth. The procedure for making Figure 4.1.1 is 

 as follows. First, we calculate the bladder oscillation parameter Z 

 for an array of horizontal ranges, x, and depths, y; i.e., Z = f(x,y). 

 These values, Z = 100 In (AMAX/AMIN) , are tabulated in Table 4.1.1. 

 Next, assuming that injury of level 3 constitutes kill, we read from 

 Figure 3.2.2 the value, Z,- no = 120, for 50% kill probability. Finally, 

 we plot in Figure 4.1.1 the regions of Table 4.1.1 having Z areater 

 than Z 50% . 



To calculate Z in Table 4.1.1 we first calculated an approxi- 

 mate pressure-time signature by the method described in Appendix C. 

 Then, we calculated the response to this signature as described in 

 Section 2 and in Appendix B, except that these computations were for 

 undamped oscillatory bladder response.* 



Figure 4.1.2 shows predicted regions of greater than 10%, 50% 

 and 90% kill for 21.5-cm long White Perch for 32 KG pentolite at 9 

 meter depth. The procedure for making Figure 4.1.2 was the same as 

 described for Figure 4.1.1. Values of Z,-. = 77 and Z orio = 190 read 

 from Figure 3.2.2 were used to obtain the 10% and 90% kill contours 

 in Figure 4.1.2. In Figure 4.1.2 contour details such as shown in 

 Figure 4.1.1 have been smoothed out. 



Note two important features of our solution to the fish-kill 

 problem which are evident in Figure 4.1.2: 



(1) The fish-kill is strongly dependent on the depth of 

 the fish. 



*Due to "no damping" and because of discrepancies between the negative pressures 

 and durations calculated by Appendix C and results from the 1975 test series 

 these calculations are considered approximate — but quite adequate for the 

 purposes of this report. 



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