1996 Fiscal Year Final Research Report Summary
On Control and Effective Use of Flow around a Cylinder by Impingement of Rectangular Jet
| Project/Area Number |
07650196
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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 | Shinshu University |
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Principal Investigator |
TSUCHIYA Yoshiaki Shinshu University, Faculty of Engineering, Professor, 工学部, 教授 (10020992)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Toshihiko Shinshu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60021010)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Rectangular jet / Impingement to body / Flow control and effective use |
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| Research Abstract |
A long circular cylinder with the diameter of 3mm, 10mm or 20mm is placed in the cross section centerline of an air jet, issuing from the rectangular orifice with the short side of 3mm and the aspect ratio of 10. The cylinder is settled in the two different arrangements ; along the short side of the exit and long one. The impinging distance between the jet exit and the surface of cylinder is at the most ninety times of the short side length. The exit velocity is kept constant at 24m/s and Reynolds number, based on the short side length, is 4900. Experiments have been carried out mainly as to the fundamental characters. The pressure profile around the cylinder and the drag of cylinder, estimated by the measured pressure, vary markedly as the impinging distance and the cylinder diameter. The flow patterns, observed on the cylinder surface by the oil-film, indicate that the cylinder positions as well as the cylinder diameter have influence on the surface flow along the circumference of cylinder. The appreciable changes of the jet impingement flow, visualized by the smoke of dry ice, are shown to be related the pressure and flow pattern on the cylinder surface.
An attempt has been made to clarify some distinctive behavior as to the complex impingement flow. Taking into account of the results derived from the related studies with respect to the edge-tone or the flow around a cylinder near a flat plate in a two-dimensional jet, experiments are still continuing to understand more systematically the effect of the parameters. More detailed studies as for pressure- and velocity-fluctuations are particularly needed to examine the concerns on self-excitation or the sound generation of the three-dimensional jet flow.
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