Research on the interactions between compressible vortex rings and the properties of generated shocklets

可压缩涡环相互作用及产生激波特性研究

• 批准号: 08650230
• 负责人: MINOTA Toyoko
• 金额: $ 1.34万
• 依托单位: Ariake National College of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650230/
• 关键词: compressible vortex ring; turbulent vortex ring; transition of vortex ring; shocklet; shock; vortex interaction; optical shadowgraph; shock focusing

The present study is concerned with the compressibility effects appearing in the motion of an unsteady flow that is initially subsonic. A fundamental flow, used in experiments, is the flow following behind the shock wave emitted from the open end of a shock-tube. This flow has a vortex ring at the head of the unsteady flow discharged continuously out of a shock-tube.First, the dynamic motions of a fundamental flow were studied by means of an optical shadowgraph method. Next, the phenomena appearing in more complex flows, produced by the interactions of a fundamental flow with other variables, were studied by the same method. The following results are discussed briefly below.The core of a head vortex ring includes a inner core with strongly concentrated vorticity and a vortex sheet surrounding it. These two sections become turbulent-like independently, during the process of the transition from a lamminar to a turbulent vortex ring. Afrer rearward-facing shocklets are generated within the head vortex ring, a very thin vortex ring appears in front of the head vortex ring. The thin vortex ring reverses its position to the rear of the head vortex ring reverses its position to the rear of the head vortex ring. The unsteady flow behind the head vortex ring, is excited by a weak shock wave, which results in the production of small vortex rings. These small vortex rings subsequently interact with each other, and then these small vortex rings merge with the adjacent ones.Supersonic zones develop within more complex flows, and shocklets are generated. The point of focus, at which the pressure increases dramatically, is produced as a result of these interactions between the shocklets and the small vortex ring.These results indicate that the unsteady flow following behind a head vortex ring makes significant works for the compressibility effects appearing in the present flow fields.

本研究涉及的压缩性效应出现在运动的非定常流，最初是亚音速。在实验中使用的基本流动是跟随在激波管开口端发出的激波后面的流动。这种流动在激波管连续排出的非定常流的头部有一个涡环。首先，用光学阴影法研究了基本流的动力学运动。其次，用同样的方法研究了由基本流与其他变量相互作用产生的更复杂流中出现的现象。本文简要讨论了以下结果：头部涡环的核心包括一个强集中涡量的内核和一个围绕它的涡面，在从层流涡环向湍流涡环转变的过程中，这两个部分独立地变成类湍流涡环。在头部涡环内产生后向小激波后，头部涡环前方出现一个很薄的涡环。薄涡环将其位置反转到头部涡环的后部。头部涡环后的非定常流动由弱激波激发，导致小涡环的产生。这些小涡环随后相互作用，然后与相邻的涡环合并，在更复杂的流动中形成超音速区，并产生小激波。激波与小涡环之间的相互作用产生了压力急剧增加的焦点，这表明头部涡环后的非定常流动对当前流场中出现的可压缩性效应起了重要作用。

项目成果

蓑田登世子: "圧縮性渦輪と物体の相互干渉現象" 日本流体力学会講演論文集(ながれ別冊). 15. 501-502 (1996)

Toyoko Minota：“可压缩涡环与物体之间的相互干涉现象”日本流体动力学学会会议记录（Nagare 分卷）15. 501-502 (1996)。

蓑田登世子: "平行平板面を伝播する衝撃波と渦輪の干渉" 衝撃波シンポジウム講演論文集. 15. 459-462 (1997)

Toyoko Minota：“在平行板表面和涡环上传播的冲击波之间的干涉”冲击波研讨会论文集 15. 459-462 (1997)。

T.Minota: "Interaction of shock wave traveling between parallel plates with a vortes ring" Proc.Symp.on SHOCK WAVES,JAPAN '96. 459-462 (1996)

T.Minota：“冲击波在带有涡环的平行板之间传播的相互作用”Proc.Symp.on SHOCK WAVES，JAPAN 96。

T.Minota, M.Nishida, M.G.Lee: "Head-on collision of two compressible vortex rings" Fluid Dynamics Research. 22, No.1. 43-60 (1998)

T.Minota、M.Nishida、M.G.Lee：“两个可压缩涡环的正面碰撞”流体动力学研究。

T.Minota: "Interaction of a shock wave with a vortex ring moving along a wall" Proc.Symp.on SHOCK WAVES,JAPAN '96. (to be published). (1998)

T.Minota：“冲击波与沿墙壁移动的涡环的相互作用”Proc.Symp.on SHOCK WAVES，JAPAN 96。