@techreport{oai:jaxa.repo.nii.ac.jp:00045028, author = {武田, 克己 and 西脇, 英夫 and TAKEDA, Katsumi and NISHIWAKI, Hideo}, month = {Jul}, note = {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}, title = {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}, year = {1983} }