Structural acoustic laboratories at NRL in Washington, DC

Abstract

The Physical Acoustics Branch at NRL operates three main laboratories in its prosecution of structural acoustics and related experimental programs. These laboratories serve as the Navy’s principle experimental capability for conducting small scale scattering and radiation studies in water; they are also used for developing advanced sensor technologies such as interferometric fiber optic strain sensors and for conducting some large scale studies. The most recent of these capabilities to come about is NRL’s new LSA (Laboratory for Structural Acoustics) which has several unique features. The heart of this new lab is a one-million-gallon, vibration isolated, temperature-controlled cylindrical tank. It is equipped with two in-water robotic scanners that possess 1-mil repeatability over their 14-×8-×8-ft work spaces, thus allowing for the acquisition of highly precise near-field holographic scattering and radiation data. The NRL laboratories are also equipped with state-of-the-art line and planar sources that allow for the uniform ensonification of test structures, as well as with near-field projection codes for reconstructing surface pressures, normal components of velocity, and far-field information. All laboratories are fully networked and supported by physically independent data acquisition systems that are rigorously maintained to uniform hardware and software standards.