2003 Fiscal Year Final Research Report Summary
Research on Complex Turbulent Structure by Smart Visualized Information Processing Technique
| Project/Area Number |
13650189
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Yamagata university (2003)
Kagoshima University (2001-2002) |
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Principal Investigator |
RINOSHIKA Akira Yamagata university, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00253906)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Smart Visualized Information Processing / Discrete Wavelet Transform / Turbulence / Vortex / Jet / Image Processing / Multi-resolution Analysis / Flow Measurement |
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| Research Abstract |
This study developed an application of the smart visualized image processing and wavelet technique to turbulent flow images and PIV (Particle Image Velocimetry) technique in order to improve the temporal resolution of images and to analyze multi-scale turbulent structures. It is well-known fact that flow images consist of a set of sequentially discretized images in time domain. The smart visualized image processing can convert the discretized images into continuous images based on Helmholtz equation and is effective when it is used in image processing. In this study the turbulent jet images and standard PIV images were used to evaluate the smart visualized information processing. Images of a turbulent wake with higher temporal resolution were generated, which were used to analyze the mechanism of jet flow The PIV results obtained from the generated PIV images agreed with the accurate solution. It can say that the smart visualized image processing technique is effective in both flow ima
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ge analysis and PIV system. On the other hand, the vector wavelet multi-resolution technique was apply to analyzing the three-dimensional measurement results of a high-resolution dual-plane stereoscopic PIV system for revealing a fundamental understanding of the multi-scale vortical structures in the near field of turbulent lobed jet The instantaneous three-dimensional velocity vectors were decomposed into large-and small-scale velocity fields. The instantaneous pairs of large-scale streamwise vortices can be clearly observed around the edge position of the lobed nozzle and spread outward along the lobes. The stronger small-scale streamwise vortices were found in the lobe regions, which first spread outward along the lobes and then develop to the whole measured flow field. These small-scale streamwise vortices also play an important role in enhancing mixing process. It is also found that the strength of the large-scale azimuthal Kelvin-Helmholtz vortices is higher than that of the streamwise vortices. At the downstream the stronger large-scale azimuthal vortices are concentrated in the region of jet core. Less
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