NSWC/WOL TR 7 7-90 



FISH KILLING POTENTIAL OF A CYLINDRICAL CHARGE 

 EXPLODED ABOVE THE WATER SURFACE 



1. INTRODUCTION 



The Naval Surface Weapons Center is currently carrying out a 

 program of explosive tests designed to determine the underwater 

 pressure field from a specially shaped charge exploded in air. 

 This report presents a preliminary analysis of the potential of 

 this special test configuration for inflicting unwanted fish-kill. 

 This analysis is restricted to swimbladder fish and is based on 

 the data and method developed in Reference 1. 



The method consists of an approximate calculation for the 

 extreme values of compression and extension of the fishes' gas- 

 filled swimbladder in response to the explosion pressure wave. 

 The calculations are made for the damped radial oscillations of 

 a spherical air bubble in water. The kill probability is then 

 calculated as an experimentally determined function of the ratio 

 of maximum to minimum radius during the oscillatory response. 



Test Configuration . The test configuration is equivalent, 

 for the purposes of this report, to a cylinder of H-6 explosive 

 (length /diameter ratio - 3.65, axis vertical) centrally initiated 

 at a scaled height, h/W ' - 0.182 m/kg , above the water 

 surface. Tests using three different explosive weights — 8, 1000, 

 and 64,000 lb H-6 — are considered. Table 1.1 lists the 

 pertinent test parameters. 



1. Goertner, J, F., "Dynamical Model for Explosion Injury to Fish," NSWC/WOL TR 

 76-155, Mar 1978. 



