Related Experiment Video
Updated: Mar 17, 2026
10:53
Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques
Published on: March 12, 2019
7.7K
Cross-frequency coherence and pulse propagation in a turbulent atmosphere
Vladimir E Ostashev1, D Keith Wilson1, Sandra L Collier2
1United States Army Engineer Research and Development Center, 72 Lyme Road, Hanover, New Hampshire 03755, USA.
The Journal of the Acoustical Society of America
|August 1, 2016
Summary
This study analyzes acoustic signal coherence in turbulent atmospheres, crucial for remote sensing and source localization. Findings reveal how atmospheric turbulence affects sound wave coherence and pulse intensity.
Area of Science:
- Atmospheric acoustics
- Wave propagation physics
- Turbulence modeling
Background:
- Cross-frequency coherence of acoustic signals is vital for atmospheric remote sensing and source localization.
- Understanding acoustic wave behavior in turbulent atmospheres requires advanced theoretical models.
Purpose of the Study:
- To calculate and analyze the cross-frequency coherence of acoustic waves in a turbulent atmosphere.
- To investigate the impact of atmospheric turbulence on the coherence bandwidth and mean intensity of acoustic pulses.
Main Methods:
- Utilized recently derived closed-form equations for spatial-temporal correlation functions.
- Employed the Rytov approximation to compute the mutual coherence function for plane and spherical waves.
- Calculated coherence bandwidth for various meteorological conditions and sound propagation parameters.
Main Results:
- Derived expressions for cross-frequency coherence in weak scattering regimes.
- Compared results with geometrical acoustics approximation and experimental data.
- Quantified the effect of atmospheric turbulence on acoustic pulse intensity.
Conclusions:
- The study provides a theoretical framework for understanding acoustic coherence in turbulent atmospheres.
- Results offer insights into the limitations and capabilities of acoustic sensing techniques in variable atmospheric conditions.
- Validated theoretical predictions against experimental observations, enhancing confidence in the model.
More Related Videos
07:56A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
9.1K
08:42Measurement of the Directional Information Flow in fNIRS-Hyperscanning Data using the Partial Wavelet Transform Coherence Method
Published on: September 3, 2021
3.7K
Related Concept Videos
01:24Turbulent Flow
850
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent...
850
01:30Propagation Speed of Electromagnetic Waves
4.9K
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
4.9K
01:07Laminar and Turbulent Flow
11.6K
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the...
11.6K
01:07Propagation of Waves
3.2K
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
3.2K
01:05Doppler Effect - II
5.0K
The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on the Doppler effect. Typically, a transmitter emits radio waves at a specific frequency toward the sky from a weather station. The radio waves bounce off the clouds and precipitation and travel back to the weather station. The radio frequency of the waves reflected back to the station appears to decrease if the clouds or precipitation are moving...
5.0K
01:18Boundary Layer Characteristics
771
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
771