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REPORT ON UNDERWATER EXPLOSIONS 
INTRODUCTION 
The purpose of this report is to collect in compact form what is known 
concerning certain practically important aspects of underwater explosions and their 
effects. After a few remarks concerning the role played by density changes in the 
motion of water, the typical sequence of events in an underwater explosion will be 
sketched. Then the principal parts of the sequence will be discussed in detail. For 
convenience of reference, the relevant parts of the theory of elastic waves in fluids 
are summarized in Appendix I. A bibliography of the most important publications on 
underwater explosive phenomena is given at the end of the report. 
UNITS 
Except where otherwise specified, all equations and mathematical expres- 
sions will be written in terms of absolute units, which may be thought of either as 
cgs units or as English gravitational, i.e., foot-slug-second units. When the English 
gravitational units are used, all pressures must be converted into pounds per square 
foot, and masses in pounds must be divided by g = 32.2. Numerical results will be 
cited always in English units. The density of water of specific gravity 1 is 
1.940 slugs per cubic foot 
For convenience a few equivalents are given here 
1 kilogram per square centimeter = 14.22 pounds per square inch 
14.50 pounds per square inch 
iT] 
10° dynes per square centimeter 
1 meter = 3.281 feet 
1 pound = 453.6 grams 
1 English ton = 2240 pounds 
I. GENERAL SURVEY 
1. TYPES OF MOTION 
I. GENERAL SURVEY 
1. COMPRESSIVE AND NON-COMPRESSIVE MOTION OF WATER 
The motion of water usually involves changes in its density. These changes 
may or may not have to be taken into consideration in discussing the motion. 
For the sake of convenience, the term compressive motion will be applied 
to motion in which the changes of density play a prominent role. The typical example 
of such motion is sound waves, which consist of alternate compressions and rarefac- 
tions propagated through the water at high speed.* The particle velocity, or velocity 
* about 4930 feet per second in sea water at 15 degrees centigrade or 59 degrees fahrenheit. 
