Fluids & Structural Mechanics > MPA > Physical Acoustics (PA)

ARL conducts a full-spectrum acoustics program that ranges from basic research to practical applications. Its fundamental work focuses on such topics as the basic physical mechanisms that govern vibrating structures, acoustical radiation, and the propagation and fluctuations of acoustic energy through air and water, with emphasis on ocean acoustics.

This work yields new approaches to signal propagation, noise field analysis, vibration control, structural tailoring, and signal exploitation for target detection and classification in complex environments. Through combined analytical, numerical, and experimental means, the program develops methods to translate these findings into practical use, especially as it relates to theory and model development, simulation and visualization.

Recent developments at ARL demonstrate this resident capability in acoustics and vibration. Important achievements include:

  • advanced propagation model for acoustic behavior in the wake of a surface ship,
  • progress in the development of acoustic vector sensors,
  • explanation of signal statistics as influenced by small scale thermohaline intrusions,
  • development of a wideband, wide area seafloor physical property survey method,
  • and development of a thermoacoustic AC power generator for both large industrial applications and the individual soldier.

The program´s research facilities include:

  • a flow-through anechoic chamber ideally suited for measuring fans and blowers
  • a structural acoustics laboratory that has a fabrication facility for unsteady pressure and force instrumentation
  • a large tank for in-water testing including complex sonars and its facility for testing and calibrating underwater acoustic transducers and arrays

These facilities are coupled with the Laboratory´s signal processing equipment to provide comprehensive data collection and analysis.

These unique acoustics and vibration capabilities are available to meet the needs of government and industry. They can be employed in efforts ranging from basic studies to management and completion of major design and development projects.

Potential Applications

  • Structural damping
  • Vehicle noise reduction
  • Aircraft powerplant noise attenuation
  • Models for sound-field propagation
  • Environmental modeling and monitoring
  • Undersea target detection and classification
  • Undersea command and control

The mission of Physical Acoustics is to study fundamental physical and acoustical processes and to utilize our understanding of those processes to develop novel techniques and products that are valuable for scientific measurement and applications to military systems and to industrial and commercial products. These efforts include collaboration between ARL staff and graduate students, since our mission includes the development of the talent base which will accelerate the transition of these advances from the laboratory to our customers and will educate the next generation of inventors.

Work done by the group ranges from modeling and measuring the effects of molecular agitation on low-noise sensors to the investigation of thermoacoustic efficiency in intense sound fields. While working from strong foundations in physical theory, the emphasis is on translating physics to hardware through a wide range of prototyping facilities and ARL shop facilities.

Research areas include:

  • Thermoacoustic refrigeration
  • Thermoacoustic energy conversion
  • Acoustic gas-contaminant analysis
  • Basic sensor physics
  • Fundamental noise mechanisms and sensor limitations
  • Electroacoustic reciprocity calibration
  • Adaptive sensors
  • Novel acoustic transduction mechanisms and devices
  • Acoustical determination of elastic properties of solids