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TECHNICAL COMMITTEE REPORT
Joseph (Josh) Gladden
Postal:
University of Mississippi 145 Hill Drive University, MS 38677 USA
Email:
jgladden@olemiss.edu
Physical Acoustics
Members of the Physical Acoustics Technical Committee have varied interests related to the physics underlying acoustic wave generation, propagation, and detection.
The Technical Committee on Physical Acoustics (TCPA) of the Acoustical Society of America (ASA) includes scientists and engineers with an interest in the un- derlying physics of acoustical phenomena. This is a necessarily broad statement. TCPA is rather unique among the other technical committees in ASA in that it is not focused on a particular application or context in which acoustics plays an important role. Instead, what unifies the members of TCPA is more about the ap- proach to answering a particular question. The types of phenomena of interest to the physical acoustics community are fundamental acoustic wave propagation, including transmission, reflection, refraction, interference, diffraction, scattering, absorption, and dispersion of sound. There is also interest in the use of acoustics to study the physical properties of matter and to produce changes in these proper- ties. TCPA currently has about 575 members with a primary interest in physical acoustics with 100–150 typically attending open TCPA meetings.
The specific types of problems that interest the physical acoustics community are incredibly varied. Walking into a random TCPA session, one might hear about acoustics in media as disparate as the upper reaches of the atmosphere to solid- state systems under extreme pressure and the use of tools and techniques appro- priate to the entire acoustic spectrum from infrasound to ultrasound. I list a few here just to give a flavor, noting this list is far from exhaustive. For example, some of the topics covered by the TCPA might include propagation in solids, liquids, and gases (homogeneous and inhomogeneous) as well as acoustic coupling be- tween these various states of matter; therapeutic, focused ultrasound in human tissue; the use of acoustic resonances to study critical phenomena in physics; the effect of a nozzle design to reduce the noise produced by a jet engine; use of acous- tics to detect buried objects in soils and sands; the interaction of sound with light and other forms of radiation; the use of resonances to enhance or enable chemi- cal reactions; production and long-range propagation of infrasound in the atmo- sphere; non-linear propagation and shocks; and the use of acoustics to control and manipulate fluid flow on a microscopic scale.
One of the great things about the acoustics community is that it brings together groups of scientists and engineers from a wide range of backgrounds, training, expertise, and interests. TCPA exemplifies this cross-disciplinary nature very well. The TCPA membership list includes people in large research universities and small liberal arts colleges, private industry and the military, and individuals with phys- ics, engineering, and biomedical backgrounds. It should be noted, however, that this breadth is a double-edged sword for ASA. There are whole research commu- nities rooted in acoustics that do not come to ASA meetings, opting instead for more focused conferences. Jet and rocket acoustics, acoustofluidics, photoacous- tics, and near-surface geophysical acoustics are a few that come to mind. TCPA has
54 | Acoustics Today | Spring 2016 | volume 12, issue 1 ©2016 Acoustical Society of America. All rights reserved.