1994 Fiscal Year Final Research Report Summary
View of the reconnection of the vortex line and its acoustic emission
| Project/Area Number |
05650186
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Ariake National College of Technology |
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Principal Investigator |
MINOTA Toyoko Electronics and Information Engineering, Professor, 電子情報工学科, 教授 (70037852)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Reconnection of Vortex Line / Compressible Vortex Ring / Shock-Vortex Interaction / Shadowgraph of Vortex Ring / Vortex Sound / 渦音 |
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| Research Abstract |
Optical experimental studies have been performed to understand flowfield and vortex structures in the head on collision and the oblique collision of two compressible vortex rings, and in the vortex ring approaching a plane wall.When the vortex ring comes close to the rigid wall, a strong separation bubble is generated from the wall boundary layr induced by the ring and the following flow and develops the secondary vortex.
It is seen in all cases that an inward facing new shock is formed between the cores of two vortices approaching each other.The formation of this shock is the same mechanism in the convergent-divergent nozzle flow.It means that the strong vortex cores act in a way similar to the nozzle.As the two vortex rings approach, the instability with the small-amplitued and short-wavelength develops on the vortex core lines.The wavy vortex core lines begin to wind round at the point of contact.The vortex lines coming into a head-on collision are stretched in the radial direction at the high speed, and expand to a turbulent cloud around the vortex core lines.In the oblique collision, the vortices at the contact points stretches and coil around the vortex line.The anti-parallel vortices are canceled and the vortex lines show the structure of the reconnection.Morphological structures on the process of reconnection of the vortex lines resemble to computed vortex structures.The secondary vortex ring developing from the separation bubble rise from the wall, and get in the interior of the primary vortex from the outside.The sound waves generate in all cases when the vortex cores wind round each other.
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