2026-03-05T21:18:01Z https://jaxa.repo.nii.ac.jp/oai

oai:jaxa.repo.nii.ac.jp:00045028 2023-06-20T21:46:34Z 1887:1893 1896:1898:1913:1917

Suppression of Peak Noise by Reshaping Coaxial Flow Circumferentially under Static Conditions ファンエンジン排気ノズルの形状変化による騒音低減の研究 武田, 克己 西脇, 英夫 TAKEDA, Katsumi NISHIWAKI, Hideo The combination of a circular fan/elliptic core nozzle was tested and compared with the results of a conventional circular core/circular fan nozzle under static flow conditions. The results show that there occurred a change of the directiveness of jet noize around the nozzle when using the circular/elliptic nozzle combination. In a 30～50deg direction from the jet axis, a 3～5 dB reduction was observed. We measured radial velocity distribution by using LDV and axial sound source distribution by the polar correlation method in an anechoic room. Based on these measurments we discuss, in this paper, the relation between sound pressure generation and velocity distribution around the exhaust nozzle. We recommend herein a circular/elliptic nozzle combination for turbo-fan engine exhaust nozzle. 資料番号: NALTR0770000 レポート番号: NAL TR-770 technical report 航空宇宙技術研究所 National Aerospace Laboratory(NAL) 1983-07 application/pdf 航空宇宙技術研究所報告 770 11 Technical Report of National Aerospace Laboratory TR-770 0389-4010 https://jaxa.repo.nii.ac.jp/record/45028/files/naltr00770.pdf https://jaxa.repo.nii.ac.jp/records/45028 jpn