Acoustical Visualization of Aeroacoustic Noise Sources : Application of Multireference Near-field Acoustical Holography (NAH)

ISBN-13: 9783639130706 / Angielski / Miękka / 2009 / 180 str.

Moohyung Lee

Opis

To perform effective noise control, it is essentialthat the detailed character of the noise source bewell understood. Near-field Acoustical Holography(NAH) is a powerful tool for visualizing noisesources and thus for identifying the detailed natureof a source. NAH has been applied most often forvisualizing structure-borne and machinery noisesources. In this book, it is shown how NAH can beapplied with equal success to aeroacoustic sources. Adetailed development of multireference NAH isprovided to allow the use of a scanning microphonearray. Also, methods for compensating for sourcenonstationarity and for extrapolating sound fieldsbeyond the measurement aperture to improve theaccuracy of the source imaging are described.Experimental results are givenfor a ducted fan and for a free jet, and it is shown,for example, that nearfield measurements allow theaccurate prediction of a source s farfielddirectivity. The analysis presented in this book willhelp scientists and engineers concerned withvisualizing aeroacoustic sources, in particular, andmore generally, any practical machinery noisesources that comprise severaluncorrelated or partially correlated subsources.

O autorze

Moohyung Lee: Earned his degrees in Mechanical Engineering. B.S.
and M.S. from Seoul National University, Korea, and Ph.D. from
Purdue University, USA. Worked for Hyundai Motor Company Research
Center. Postdoctoral Researcher at the Ray W. Herrick
Laboratories, Purdue University. Research on Acoustics,
Vibration, and Signal Processing.