@techreport{oai:jaxa.repo.nii.ac.jp:00044780,
 author = {藤井, 昭一 and 西脇, 英夫 and 武田, 克巳 and FUJII, Shoichi and NISHIWAKI, Hideo and TAKEDA, Katsumi},
 month = {Feb},
 note = {This paper describes an experimental measurement of the effects of uneven blade spacing on the acoustic and aero-thermodynamic characteristics of high-speed, high-pressure-ratio fan rotors at two selected spacing configurations. A test rig, consisting of inlet guide vanes and transonic rotor blades, was employed to explore the redistribution of harmonic sound energy into a series of multiple tones of lower sound pressure level. The measured data indicated that a 10％ modulated rotor exhibited a six to eight decibel decrease in the sound pressure level as compared with the original first blade passage frequency harmonic. Disadvantages in aerodynamic performance resulting from spacing modulation were not so unfavourable for 10％ modulated blades. However, with 5％ modulated blades, serious deterioration in aerodynamic performance was observed particularly near the blade tip section, which produced an unfavourable acoustic signature. A calculation method, assuming a pulse event for each blade sound pressure, provided agreeable results with the measured data., 資料番号: NALTR0526000, レポート番号: NAL TR-526},
 title = {不等ピッチで高速回転するファンの音響特性と空力性能},
 year = {1977}
}