An Experimental Study on Side Flow Stabilization by using Stepped Nosed Method

• Material Type: 規格・テクニカルリポート類
• Title: An Experimental Study on Side Flow Stabilization by using Stepped Nosed Method
• Author/Editor: Cakrawala, Anang; Umemura, Akira
• Author Heading: Cakrawala, Anang; Umemura, Akira
• Publication, Distribution, etc.: 航空宇宙技術研究所
• Publication Date: 2003-06
• Publication Date (W3CDTF): 2003
• Periodical title: 独立行政法人航空宇宙技術研究所特別資料 = Special Publication of National Aerospace Laboratory SP-59
• No. or year of volume/issue: 59
• Volume: 59
• Pages: 4-
• ISSN (Periodical Title): ISSN : 1347-457X
• Target Audience: 一般
• Note (General): 出版タイプ： NA; Experimental study on fluid flow characteristics around step obstacle at angle of attack zero were carried out for Reynolds number in the range 0.5x10^5 to 1.5 10^5. Previous experiment study shows optimum stepped configuration obtains for some case of step height. In order to understand the structure of fluid flow around optimum configuration of the stepped nosed obstacle, we has been carry out an experimental study by using stepped nosed model result in various step height and stepped length. A small rectangular attached to a square cylinder, which is configure various stepped nosed obstacle, reduced the drag coefficient significantly. The underlying physics are that (1) the vortices trapped in the step regions produce the thrust forces acting on the step surfaces facing against the uniform stream which cancel the drag force acting on the front surface of the stepped nose obstacle and that (2) the tangent reattachment of the flow separating from the front surface edges to the side surfaces of the main body decreases the suction pressure acting on the back surface of the main body. In the present study, we would like to clarify the flow structure at the optimum stepped configuration. The optimum stepped configuration means the stepped nosed obstacle with minimum drag force. It is also examine the effect of Reynolds number for optimum stepped configuration. This paper describe experimental result on the optimum stepped configuration include the following: A. Stepped obstacle drag coefficient map. B. Surface pressure distribution C. Flow visualization D. Strouhal number measurement Experimental results shows there is no significant Reynolds number effect in case Re between 0.5 10^5 ～ 1.5 10^5. Since Separation on bluff body such as stepped nosed obstacle occurs directly from the both front corner. The flow on side surface of the stepped obstacle shows stable, low turbulence intensity and almost attach to side surface of the obstacle. This condition result to narrow wakes and increase Strouhal number.; 資料番号: NALSP0059008; レポート番号: NAL SP-59
• Periodical Title (NCID): AN10097345; https://ci.nii.ac.jp/ncid/AN10097345
• Data Provider (Database): 国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）; https://irdb.nii.ac.jp
• Original Data Provider (Database): 宇宙航空研究開発機構 : 宇宙航空研究開発機構リポジトリ