Patch near-field acoustical holography in cylindrical geometry

Multisource statistically optimized near-field acoustical holography.

This paper presents a reduced-order approach to near-field acoustical holography (NAH) that allows the user to account for sound fields generated by multiple spatially separated sources. In this method, an equivalent wave model (EWM) of a given field is formulated to include combinations of planar, cylindrical, spherical, or other elementary wave functions in contrast to an EWM restricted to a ...

Cylindrical acoustical holography applied to full-scale jet noise.

Near-field acoustical holography methods are used to predict sound radiation from an engine installed on a high-performance military fighter aircraft. Cylindrical holography techniques are an efficient approach to measure the large and complex sound fields produced by full-scale jets. It is shown that a ground-based, one-dimensional array of microphones can be used in conjunction with a cylindr...

The Characterization of the Cylindrical Ultrasonic Transducer Surface Vibration Using Far-field Acoustical Holography

The paper presents the results of investigation on the distribution of vibrational velocity on the surface of the cylindrical piezoelectric ultrasound transducers using far-field acoustical holography. In contrast to the plane and focused transducers, for which method of acoustic holography using the Rayleigh integral is applicable [1], cylindrical sources require scanning over a closed surface...

Source Visualization by Using Statistically Optimized Near-Field Acoustical Holography in Conical Coordinates

Compensation for source nonstationarity in multireference, scan-based near-field acoustical holography.

Multireference, scan-based near-field acoustical holography is a useful measurement tool that can be applied when an insufficient number of microphones is available to make measurements on a complete hologram surface simultaneously. The scan-based procedure can be used to construct a complete hologram by joining together subholograms captured using a relatively small, roving scan array and a fi...