Langley Research Center (LaRC) has for years been a leader in field acoustic array measurement technique. Two field-deployable digital measurement systems have been developed to support acoustic research programs at LaRC. For several years, LaRC has used the Digital Acoustic Measurement System(DAMS) for measuring the acoustic noise levels from rotorcraft and tiltrotor aircraft. Recently, a seco...

A polymer gel (ferrogel) is an assembly of ferromagnetic nanoparticles embeded in gel. In the ferrogel, the finely distributed magnetic particles are suspended in the swelling liquid and forma flexible matrix due to adhesive forces. The present paper describes an electric and acoustic study of magnetic field sensitive poly (dimethyl siloxane) ferrogel. The results showed hysteresis of acoustic ...

We present a novel approach for optimizing acoustic parameters using sensitivity analysis for computer-aided design and analysis of architectural models. Our approach builds on recent low-dispersion wave-based acoustic solvers that can accurately compute the pressure field in large models. We present an efficient technique to compute the gradient of the pressure field using automatic differenti...