Browsing by Subject "Bubbles"
Now showing items 1-11 of 11
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Acoustical probing for microbubbles at sea
(NATO. SACLANTCEN, 1975/10)Free gas bubbles have been indicted for many physical processes at sea including: scavenging detritus and chemicals from the ocean volume; generating droplets whose salts affect thunderstorm activity over the sea; providing ... -
Analysis of broad-band echosounder data over a gassy seabed
(NATO. SACLANTCEN, 1997)Calibrated echosoundings from a well-characterized gassy seabed were examined. Acoustic reflection was significantly higher than expected. It is hypothesized that gas bubbles are responsible. Anomalously high levels of ... -
Decay of large underwater bubble oscillations
(NATO. SACLANTCEN, 1999/02)Pressure - time series from breathing mode oscillation of large (centimeter scale or larger) underwater bubbles reveal much higher decay rates than can be explained using viscous, thermal, or radiative mechanisms which ... -
Gas bubbles in the sea: a review and model proposals
(NATO. SACLANTCEN, 1975/10)The literature pertaining to both free bubbles (pt 1) and bubbles associated with fish anotomy (pt 2) is reviewed with particular emphasis on their distributions in the sea and influencing factors. An attempt is made to ... -
Low frequency resonance backscatter from near-surface bubble clouds
(NATO. SACLANTCEN, 1993/08)When active sonar systems are used to insonate the sea surface, anomalous scattering is observed in the form of enhanced backscatter, and more importantly, in the form of discrete, bright echoes. The most plausible explanation ... -
Measurement of the bubble population in coastal waters using combination frequencies of MHz order
(NATO. SACLANTCEN, 1997)This paper describes the use of a combinatron frequency technique to measure the size distribution of oceanic bubbles. Written between two sea trials, the paper describes how the apparatus cart be adapted to design tests ... -
On the physics and design of electrical discharge sources for active undersea surveillance
(NATO. SACLANTCEN, 1993/08)Underwater electrical arcs have long been used as an impulsive sound source, although efforts to improve efficiency and control acoustic output have been limited by inadequate understanding of the arc initiation process. ... -
Shallow water propagation incorporating both bubble plumes and sea-surface roughness
(NATO. SACLANTCEN, 1997)The effect of including a range dependent bubble layer and a suitable sea surface spectrum in modeling shallow water propagation is analyzed. Propagation is simulated through a hrghly accurate model based on a modified PE ... -
The effect of water column stability on acoustic backscatter from the ocean bubble layer
(NATO. SACLANTCEN, 1997)