Study on the Compressible Turbulence Produced by the Interaction of a Laser Induced Shock Wave and Strong Vortex Ring with a Body

激光激波与强涡环与物体相互作用产生的可压缩湍流研究

• 批准号: 13650202
• 负责人: MINOTA Toyoko
• 金额: $ 2.43万
• 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: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650202/
• 关键词: Laser-Induced Breakdown; Plasma Shape; Laser Focusing; ShockWave; Separation Bubble; Shear Layer; Shocklet; Laser Shadowgraph; シャドウグラフ; 正方形渦ループ; ステレオ・シャドウグラフ; 小渦列; 方形渦ループの軸変更; 正方形渦輪; 剥離渦の発達; 方形渦輪の軸変更; 渦の相互作用

The present studies are concerned with laser-induced breakdown phenomena, and with the interactions between a high-speed vortex ring and a small rigid body. The aims of these studies are to observe the shock waves and the plasma state formed by focusing a pulsed Nd-YAG laser (450 mJ/pulse) in atmosphere, and to prove the effect on the separation of the boundary layer and the flow field induced around a body caused by the shape of a body. The brief conclusion for the results of the experiments by shadowgraph technique are as follows.1)A strong shock wave generated by focusing a laser propagates spherically around the plasma produced. Weak shock waves are generated inside the spherical shock wave, and catch up with the outer spherical shock wave.2)The plasma state is made up of several layers of vortices shaped like a circular disc with the axis in the direction of the laser beam. The spaces between each layer are high pressure, and oblique shocklets go out from the edges of these discs. The plasma plume is emitted in the direction of the incident laser. The plasma occasionally goes into explosion which produces strong shock waves. The plasma is split in half, or a fragment of the breakup plasma comes apart the main and flies away. The outer spherical shock wave is influenced sharply by it.3)As a circular vortex ring approaches a small body, a boundary layer is induced on the side face of the body. In a sharp edge body, an array of small vortices is formed between the edge of the body and the wall vortex core. In a blunt body, an inward-facing shocklet is formed near the separation point. The differences in these flow fields are caused by the velocity of the flow between the body and the vortex ring at the time that the separation bubble is induced.

本文研究了激光诱导的破裂现象，以及高速涡环与小刚体的相互作用。这些研究的目的是观察由脉冲Nd-YAG激光（450 mJ/pulse）在大气中聚焦形成的冲击波和等离子体状态，并证明物体形状对边界层分离和物体周围诱导的流场的影响。对阴影技术实验结果的简要总结如下：1）激光聚焦产生的强冲击波围绕产生的等离子体球形传播。在球形激波内部产生弱激波，并追上外部球形激波。2）等离子体状态由若干层涡旋组成，形状类似圆盘，轴线与激光束方向一致。每一层之间的空间是高压的，斜激波从这些圆盘的边缘出来。等离子体羽流沿入射激光的方向发射。等离子体偶尔会发生爆炸，产生强烈的冲击波。等离子体分裂成两半，或者分裂的等离子体碎片与主离子体分离并飞走。当圆形涡环靠近小物体时，在物体侧面诱导出边界层。在锐缘物体中，在物体的边缘和壁涡核之间形成小涡阵列。在钝头体中，在分离点附近会形成一个向内的小激波。这些流场的差异是由分离气泡产生时物体和涡环之间的流速引起的。

项目成果

Minota Toyoko: "Shock formation through the interaction of a solid sphere and a vortex ring"Proc.23^<rd> International Symposium on Shock Wave, No.3190. 1521-1527 (2002)

Minota Toyoko：“通过实心球和涡环的相互作用形成激波”Proc.23^<rd>国际冲击波研讨会，No.3190。

T.MINOTA: "Flow field induced by the interaction of a solid cube and a high-speed vortex flow"Proc. Sym on SHOCKWAVES, JAPAN. 37-40 (2001)

T.MINOTA：“固体立方体和高速涡流相互作用引起的流场”Proc。

Minota Toyoko: "The flow-field around a small square plate interaction with the vortex flow released from a shock tube"Shock Waves 2004 Proc.24^<th> Int.Symp.on Shock Waves. (印刷中). (2004)

Minota Toyoko：“小方板周围的流场与激波管释放的涡流相互作用”Shock Waves 2004 Proc.24^<th> Int.Symp.on Shock Waves（2004 年出版）。

T.MINOTA: "Shock formation through the interaction of a solid sphere and a vortex ring"Shock Waves 2001 Proc. 23rd Int. Sym on Shockwaves. 1521-1527 (2001)

T.MINOTA：“通过实心球和涡环相互作用形成激波”Shock Waves 2001 Proc。

T.MINOTA: "The flow field induced by the interactions of a small solid body with corner and a high-speed vortex flow"Proc. Japan Con., on High Speed Photography and Photonics 2003. 147-152 (2001)

T.MINOTA：“小固体与角点和高速涡流相互作用引起的流场”Proc。