The Acoustic Output of Explosive Charges 



Ermine A. Christian 



White Oak Laboratory 



Naval Surface Weapons Center 



Silver Spring, Maryland 



Although small explosive charges are widely used as 

 sources for underwater acoustics studies, a number of un- 

 resolved questions exist concerning the proper source 

 levels for use in data analysis. At the present time 

 there is no generally accepted "standard" set of source 

 levels, and deviations of 5 to 10 dB can be found among 

 published values. Better information is needed to define 

 a reference range beyond which finite amplitude effects 

 are negligible. Spectral energy levels are sensitive to 

 charge detonation depth, an experimental variable that 

 typically is not controlled in acoustic experiments. 

 These and other problem areas associated with explosion 

 sources are reviewed with comments on their quantitative 

 effects at low frequencies. 



INTRODUCTION 



I am well aware that the members of this acoustic community are 

 not, in general, entranced with the beauties of explosions physics. 

 It is a delightfully complex subject that is simply a pain in the neck 

 to someone who wants a neat, simple source for underwater acoustics 

 research work. 



Unfortunately, in today's sophisticated world we are trying to 

 do a number of rather closely controlled experiments. We are looking 

 for subtle effects, small differences, and we are looking for detailed 

 frequency dependencies rather than the broad-brush quantities that 

 sufficed a decade ago. This means we can no longer gloss over inherent 

 characteristics of the pressure waves generated by explosions, even 

 though they may be uncomfortably complicated. So let me be a purist 



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