What We Do
The Acoustics Department studies the propagation and scattering of sound. Historically our primary focus has been the ocean and on structures in the ocean using theory and numerical modeling backed by ocean experiments. In the next ten years we plan to strengthen our non-ocean related research efforts.
Our research spans the frequency range from a few hertz to hundreds of kilohertz. We seek to understand and quantitatively predict propagation and scattering (the ‘forward’ problem). These predictions require detailed knowledge of the environment and the material properties of targets. To measure the ocean environment, we collaborate with physical, biological and geophysical oceanographers. Those same collaborations are essential to our development of acoustical oceanography techniques (the ‘inverse’ problem).
A forward problem in environmental acoustics asks, "Given the environment, what is the received signal?" High fidelity forward models then allow us to address the inverse problem, "Given recorded acoustic data, what is the environment?" Solving the forward problem requires a combination of physical understanding, theoretical development, and analytic and numerical modeling. The inverse problem offers many challenges as well, since it may be nonlinear, non-unique, and sensitive to uncertainty in environmental properties and the details of the acoustic data.
Acoustic propagation and scattering from volume heterogeneities and surface roughness
- Undersea acoustic communications
- Remote sensing of the environment
- Acoustical oceanography
- Scattering from objects deployed in the ocean
- Ambient noise in air and underwater environments
- Measurement and control of underwater industrial noise
- Arctic acoustics
Philip Marston, WSU
TREX13: Target and Reverberation EXperiment 2013
This ocean acoustics experiment measured mid-frequency reverberation and the abilities to detect and classify unexploded ordnance and mine-like targets on the seafloor using synthetic aperture sonar in a shallow water environment off Panama City, FL. More >>
History of Acoustics Research at APL-UW Six Decades of Acoustics Research at APL-UW, presented by Kevin Williams at the Acoustical Society of America meeting in Pittsburgh, PA, May 2015. (YouTube video)
Using Vector Sensors to Measure the Complex Acoustic Intensity Field David Dall’Osto and Peter Dahl (PPT 37 MB)
Acoustic Color of Mines & Mine-Like Objects Kevin Williams, Steven Kargl, Aubrey España (PDF 3 MB)
Acoustic Detection of Unexploded Ordnance Aubrey España's presentation at the 31 Oct 2011 Acoustical Society of America's Webcast on Discoveries in Acoustics (Quicktime Movie, 64 MB)
Acoustic Intensity Properties in an Ocean Waveguide David Dall-Osto, Peter H. Dahl (PPT 2 MB)
Modeling a Spiral Wave Front Source in an Ocean Environment Brian T. Hefner, Benjamin R. Dzikowicz (PDF 15.6 MB)
Pressure-particle Velocity Coherence David Dall-Osto, Peter H. Dahl (PPT 3 MB)
Physics-Based Inversion of High-Frequency Multibeam Sonar Data Darrell Jackson and Brian T. Hefner (PDF 250 Kb)
In the News
Washington Sea Grant Sea Star
25 Jul 2016
Acoustical engineers show how seabed terrain affects sound waves and how marine construction can cost less and still protect marine mammals.
Some whales like global warming just fine
National Geographic, Isabelle Groc
5 Apr 2016
Humpbacks and bowheads are benefiting for now, at least from the retreat of polar sea ice: It's making it easier for them to find food.
Ivakin, A., "A full-field perturbation approach to scattering and reverberation in range-dependent environments with rough interfaces," J. Acoust. Soc. Am., 140, 657-665, doi:10.1121/1.4959111, 2016.
1 Jul 2016, Link
Sarma, V.V.S.S., et al., including K.M. Stafford," Effects of freshwater stratification on nutrients, dissolved oxygen, and phytoplankton in the Bay of Bengal," Oceanography 29, 222–231, doi:10.5670/oceanog.2016.54, 2016.
1 Jun 2016, Link
Tandon, A., E.A. D’Asaro, K.M. Stafford, D. Sengupta, M. Ravichandran, M. Baumgartner, R. Venkatesan, and T. Paluszkiewicz, "Technological advancements in observing the upper ocean in the Bay of Bengal: Education and capacity building," Oceanography 29, 242–253, doi:10.5670/oceanog.2016.56, 2016.
1 Jun 2016, Link
Graduate and undergraduate students can work under the tutelage of the Acoustics Department investigators through their respective home UW academic colleges, including oceanography, engineering, and earth and space sciences. More >>
Dr. Peter Dahl, for example, teaches Applied Acoustics (Mechanical Engineering 525), which introduces acoustics through its various applications and sub-fields, such as underwater sound (inlcuding sonar), medical ultrasound, and noise control and vibration.