Detection of underwater sound sources by microwave radiation reflected from the water surface

1972 ◽  
Vol 60 (6) ◽  
pp. 741-742
Author(s):  
D.E. Tremain ◽  
D.J. Angelakos
Keyword(s):  
Microwave Radiation ◽  
Water Surface ◽  
Underwater Sound ◽  
Sound Sources

The entrainment of bubbles by drop impacts

1990 ◽  
Vol 220 ◽  
pp. 539-567 ◽  
Author(s):  
Hugh C. Pumphrey ◽  
Paul A. Elmore
Keyword(s):  
Water Surface ◽  
Capillary Waves ◽  
Experimental Results ◽  
Single Bubble ◽  
Underwater Sound ◽  
The Third ◽  
Entrainment Process ◽  
Drop Impacts ◽  
The Impact ◽  
Small Bubbles

Various processes are described by which a drop of water, impacting on a water surface, may entrain a bubble. There are: (i) irregular entrainment, in which the complex details of a splash entrain bubbles; (ii) regular entrainment, in which the crater formed by the drop impact develops in a predictable way to form a single bubble; (iii) entrainment of large bubbles, in which most of the volume of the crater is trapped as a bubble; and (iv) Mesler entrainment, in which many very small bubbles are trapped in the very early stages of the impact process; possibly between wave crests of capillary waves which develop on the drop and on the water surface. This last process is different from the preceding three in that it produces very little sound. All of the processes except the third one have been described individually in the literature; here we present them together for comparison. The regular entrainment process is discussed in the greatest detail and some new experimental results are presented which concern the size and nature of the entrained bubbles. The significance of the regular and irregular entrainment processes to the generation of underwater sound by rain is discussed.

Magnetoacoustics and Thermoacoustics—New Ideas in Underwater Sound Sources

1963 ◽  
Vol 2 (2) ◽  
pp. 33-38
Author(s):  
Emil J. Hellund ◽  
John T. Naff ◽  
Robert C. Brumfield
Keyword(s):  
Underwater Sound ◽  
Sound Sources ◽  
New Ideas
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