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ABSTRACT 



This raport presents measurements of the periods of oscillation and 

 the radii at raaximura size of bubbles of product gases from underwater 

 explosions. The significance of these measurements is discussed as it 

 pertains to the energy of the bubble. No attempt is made to relate this 

 energy to the energy emitted by the bubble in the form of a pressure wave 

 or "bubble pulse" at the time of the bubble minimum, 



A large number of piezoqlectrically recorded period measurements 

 are reported for chaiges weighing from 1 cz to l/2 lb. Maximum radii, 

 obtained from simultaneous photographic records are also shown. The 

 charges were fired at depths ranging from 2 to 700 ft. 



An .anaJ-ysis of the data is made, based on the theory as developed by 

 Shiffman and Friedman. Their numerical integrations of the period have 

 been extended to include a ?ri.der range of the parameters which describe 

 the internal energy of the product gases. By making reasonable assumptions 

 in the calculations, the energy of the bubble is computed to be about 5056 

 of the total energy released by the detonation. It is shown that there is 

 some uncertainty in these calculations due to the limited range of the 

 experiments and the lack of definite knowledge as to the state of the 

 gases in the bubble. 



