Mitigation of low-frequency underwater sound using large encapsulated bubbles and freely-rising bubble clouds

Author(s):  
Kevin M. Lee ◽  
Kevin T. Hinojosa ◽  
Mark S. Wochner ◽  
Theodore F. Argo IV ◽  
Preston S. Wilson
2011 ◽  
Vol 129 (4) ◽  
pp. 2462-2462 ◽  
Author(s):  
Kevin M. Lee ◽  
Kevin T. Hinojosa ◽  
Mark S. Wochner ◽  
Theodore F. Argo ◽  
Preston S. Wilson

1994 ◽  
Author(s):  
Peter H. Rogers ◽  
Gary W. Caille ◽  
Thomas N. Lewis

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3674 ◽  
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Rongzhen Guo ◽  
Qicheng Zhang ◽  
Shichang Li ◽  
...  

A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite element modeling (FEM)of the transducer was established for simulating the vibration modes and the acoustic characteristics of the transducers. Further, we fabricated a spiral sound wave transducer based on our design and simulations. It was found that the resonance frequency of the transducer was 10.8 kHz and that the transmitting voltage resonance was 140.5 dB. The underwater sound field measurements demonstrate that our designed transducer based on the longitudinal elements could successfully generate spiral sound waves.


2015 ◽  
Author(s):  
Kevin M. Lee ◽  
Andrew R. McNeese ◽  
Preston S. Wilson ◽  
Mark S. Wochner

2010 ◽  
Vol 128 (4) ◽  
pp. 2279-2279
Author(s):  
Kevin M. Lee ◽  
Kevin T. Hinojosa ◽  
Mark S. Wochner ◽  
Theodore F. Argo ◽  
Preston S. Wilson ◽  
...  

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. P119-P128
Author(s):  
Daniel Wehner ◽  
Martin Landrø

In the seismic industry, there is increasing interest in generating and recording low frequencies, which leads to better data quality and can be important for full-waveform inversion. The air gun is a seismic source with a signal that consists of the (1) main impulse, (2) oscillating bubble, and (3) rising of this air bubble. However, there has been little investigation of the third characteristic. We have studied a low-frequency signal that could be created by the rising air bubble and find the contribution to the low-frequency content in seismic acquisition. We use a simple theory and modeling of rising spheres in water and compute the acoustic signal created by this effect. We conduct tank and field experiments with a submerged buoy that is released from different depths and record the acoustic signal with hydrophones along the rising path. The experiments simulate the signal from the rising bubble separated from the other two effects (1 and 2). Furthermore, we use data recorded below a single air gun fired at different depths to investigate if we can observe the proposed signal. We find that the rising bubble creates a low-frequency signal. Compared with the main impulse and the oscillating bubble effect of an air-gun signal, the contribution of the rising bubble is weak, on the order of 1/900 depending on the bubble size. By using large air-gun arrays tuned to create one big bubble, the contribution of the signal can be increased. The enhanced signal can be important for deep targets or basin exploration because the low-frequency signal is less attenuated.


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