{"created":"2023-06-20T15:07:45.225938+00:00","id":37119,"links":{},"metadata":{"_buckets":{"deposit":"53fd7848-9852-4ac5-ae87-a69b5d94b175"},"_deposit":{"created_by":1,"id":"37119","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"37119"},"status":"published"},"_oai":{"id":"oai:jaxa.repo.nii.ac.jp:00037119","sets":["1887:1891","1896:1898:1913:1915"]},"author_link":["478994","478993","478995","478996"],"item_5_alternative_title_2":{"attribute_name":"その他のタイトル（英）","attribute_value_mlt":[{"subitem_alternative_title":"On aerodynamic sound and large scale eddies in the wake of a circular cylinder"}]},"item_5_biblio_info_10":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1997-12","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"120","bibliographicPageStart":"117","bibliographicVolumeNumber":"36","bibliographic_titles":[{"bibliographic_title":"航空宇宙技術研究所特別資料"},{"bibliographic_title":"Special Publication of National Aerospace Laboratory","bibliographic_titleLang":"en"}]}]},"item_5_description_14":{"attribute_name":"会議概要（会議名, 開催地, 会期, 主催者等）","attribute_value_mlt":[{"subitem_description":"航空宇宙技術研究所 26-28 Mar. 1997 東京 日本","subitem_description_type":"Other"}]},"item_5_description_15":{"attribute_name":"会議概要（会議名, 開催地, 会期, 主催者等）（英）","attribute_value_mlt":[{"subitem_description":"National Aerospace Laboratory 26-28 Mar. 1997 Tokyo Japan","subitem_description_type":"Other"}]},"item_5_description_16":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"放射空力音と表面圧力変動のコヒーレンス長の関係に注目して円柱からの空力音を予測した。表面圧力変動のスパン方向コヒーレンス関数の積分スケールとして定義されるコヒーレンス長L(sub c)を実験により推定した。測定した表面圧力変動とL(sub c)を適用した変形Curle方程式により空力音スペクトルを試算した。基本振動数の5倍程度までは、放射空力音の予測スペクトルは実測スペクトルとよく一致した。L(sub c)が表面圧力変動を利用して放射空力音の性質を推定するのに適切なインデックスとして働くことが判明した。基本周波数におけるスパン方向コヒーレンス関数がガウス関数であり、制御パラメータとしてレイノルズ数を伴うスパン方向間隔を含むことが分かった。またコヒーレンス長L(sub c)はRe(exp 1/2)に逆比例することが明らかになった。層状円柱後流内のせん断層不安定波長は近似的にRe(exp 1/2)で概算する剥離境界層の厚さに比例する。従って、L(sub c)はせん断層不安定波長に関連していると推測した。渦度と空力音に関してコヒーレント・アウトプット・パワー(COP)を用いて空力音源分布を評価した。COPはカルマン渦の形成領域近傍で高く、X/D=1.5〜2.0、Y/D=±0.4であることが判明した。この結果は剥離せん断流が空力音生成に強く寄与していることを示した。","subitem_description_type":"Abstract"}]},"item_5_description_17":{"attribute_name":"抄録（英）","attribute_value_mlt":[{"subitem_description":"Aerodynamic sound was predicted from a circular cylinder focusing on the relationship between radiated sound and coherence length of surface pressure fluctuation. The coherence length, L(sub c), defined as the integral scale of the spanwise coherence function of surface pressure fluctuation was estimated experimentally. It was attempted to calculate sound spectra with a modified Curie's equation by using measured surface pressure fluctuations and L(sub c). Up to five times the fundamental frequency, the predicted spectra of radiated sound are in good agreement with those actually measured. Here, L(sub c) turns out to act as a good index to estimate the character of radiated sound by using surface pressure fluctuation. It was also found that the spanwise coherence function at the fundamental frequency is a Gaussian function, including spanwise spacing with Reynolds number as a control parameter, and revealed that the coherence length L(sub c) is inversely proportional to Re(exp 1/2). The wavelength of shear layer instability in the laminar wake of a circular cylinder is proportional to the thickness of separating boundary layer, which scales approximately with Re(exp 1/2). Therefore, it was speculated that L(sub c) is related to the wavelength of shear layer instability. The distribution of aerodynamic sound source was evaluated by using Coherent Output Power (COP) in terms of vorticity and aerodynamic sound. It was found that COP is high near the formation region of Karman vortices; that is, X/D = 1.5 to 2.0, Y/D = +/-0.4. This result shows that separated shear flows contribute strongly to the aerodynamic sound generation.","subitem_description_type":"Other"}]},"item_5_description_32":{"attribute_name":"資料番号","attribute_value_mlt":[{"subitem_description":"資料番号: AA0001320029","subitem_description_type":"Other"}]},"item_5_description_33":{"attribute_name":"レポート番号","attribute_value_mlt":[{"subitem_description":"レポート番号: NAL SP-36","subitem_description_type":"Other"}]},"item_5_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"航空宇宙技術研究所"}]},"item_5_publisher_9":{"attribute_name":"出版者（英）","attribute_value_mlt":[{"subitem_publisher":"National Aerospace Laboratory (NAL)"}]},"item_5_source_id_21":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0289-260X","subitem_source_identifier_type":"ISSN"}]},"item_5_source_id_24":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN10097345","subitem_source_identifier_type":"NCID"}]},"item_5_text_6":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"日立製作所 機械研究所"},{"subitem_text_value":"日立製作所 機械研究所"}]},"item_5_text_7":{"attribute_name":"著者所属（英）","attribute_value_mlt":[{"subitem_text_language":"en","subitem_text_value":"Hitachi Ltd Mechanical Engineering Research Laboratory"},{"subitem_text_language":"en","subitem_text_value":"Hitachi Ltd Mechanical Engineering Research Laboratory"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"飯田, 明由"}],"nameIdentifiers":[{}]},{"creatorNames":[{"creatorName":"大田黒, 俊夫"}],"nameIdentifiers":[{}]},{"creatorNames":[{"creatorName":"Iida, Akiyoshi","creatorNameLang":"en"}],"nameIdentifiers":[{}]},{"creatorNames":[{"creatorName":"Otaguro, Toshio","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2020-02-10"}],"displaytype":"detail","filename":"nalsp0036029.pdf","filesize":[{"value":"536.1 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"nalsp0036029.pdf","url":"https://jaxa.repo.nii.ac.jp/record/37119/files/nalsp0036029.pdf"},"version_id":"4b479b12-bdf5-4e21-85d4-45401c6cd054"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"円柱後流","subitem_subject_scheme":"Other"},{"subitem_subject":"大規模渦","subitem_subject_scheme":"Other"},{"subitem_subject":"空力音","subitem_subject_scheme":"Other"},{"subitem_subject":"コヒーレンス長","subitem_subject_scheme":"Other"},{"subitem_subject":"表面圧力変動","subitem_subject_scheme":"Other"},{"subitem_subject":"スパン方向コヒーレンス関数","subitem_subject_scheme":"Other"},{"subitem_subject":"せん断層不安定性","subitem_subject_scheme":"Other"},{"subitem_subject":"剥離境界層","subitem_subject_scheme":"Other"},{"subitem_subject":"コヒーレント・アウトプット・パワー","subitem_subject_scheme":"Other"},{"subitem_subject":"カルマン渦","subitem_subject_scheme":"Other"},{"subitem_subject":"Curle方程式","subitem_subject_scheme":"Other"},{"subitem_subject":"空力音スペクトル","subitem_subject_scheme":"Other"},{"subitem_subject":"circular cylinder wake","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"large scale eddy","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"aerodynamic sound","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"coherence length","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"surface pressure fluctuation","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"spanwise coherence function","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"shear layer instability","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"separation boundary layer","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"cohelent output power","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"Karman vortex","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"Curles equation","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"sound spectrum","subitem_subject_language":"en","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"conference paper","resourceuri":"http://purl.org/coar/resource_type/c_5794"}]},"item_title":"円柱後流の大規模構造と空力音について","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"円柱後流の大規模構造と空力音について"}]},"item_type_id":"5","owner":"1","path":["1891","1915"],"pubdate":{"attribute_name":"公開日","attribute_value":"2015-03-26"},"publish_date":"2015-03-26","publish_status":"0","recid":"37119","relation_version_is_last":true,"title":["円柱後流の大規模構造と空力音について"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-06-20T21:25:32.065234+00:00"}