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Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics
Published on: August 27, 2013
Acoustic propagation under tidally driven, stratified flow.
Steven Finette1, Roger Oba, Colin Shen
1Acoustics Division, Naval Research Laboratory, Washington, DC 20375, USA. steven.finette@nrl.navy.mil
The Journal of the Acoustical Society of America
|June 7, 2007
Summary
Simulations of acoustic fields in ocean shelf-break environments reveal that phase variability causes rapid signal decorrelation. Environmental factors like internal tides significantly impact acoustic detection ranges and transmission loss.
Area of Science:
- Ocean acoustics
- Fluid dynamics
- Wave propagation
Background:
- Acoustic field variability is crucial for underwater communication and detection.
- Ocean environments, particularly shelf breaks, exhibit complex hydrodynamic and acoustic behaviors.
- Understanding sound propagation in dynamic ocean conditions is essential for sonar performance.
Purpose of the Study:
- To simulate acoustic field variability in a shelf-break environment.
- To analyze the impact of hydrodynamics and internal tides on acoustic signals.
- To determine detection ranges and transmission loss under varying ocean conditions.
Main Methods:
- Simulated acoustic fields using sound speed distributions from hydrodynamic models.
- Incorporated tidal forcing, internal tides, and solibores.
- Computed acoustic transmission loss and field decorrelation at specific frequencies (200-500 Hz).
- Extended simulations to 3D to analyze azimuth-time variations.
Main Results:
- Acoustic field decorrelation is dominated by phase variability, occurring within 2-3 minutes.
- Significant recorrelation was observed in specific frequency subbands.
- Depth-averaged transmission loss varied up to 4 dB due to environmental factors.
- Azimuth-time variations in acoustic fields were analyzed for 100 Hz sources.
Conclusions:
- Hydrodynamic processes, including internal tides, significantly influence acoustic signal characteristics.
- Phase variability is the primary driver of rapid acoustic field decorrelation.
- Environmental conditions directly affect underwater acoustic detection ranges and system performance.
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