1997 Fiscal Year Final Research Report Summary
Formation mechanism of the reflected shock wave over curved surfaces.
| Project/Area Number |
08650220
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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 | Saitama Institute of Technology |
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Principal Investigator |
KOBAYASHI Susumu Saitama lnst.Tech., Dept.Mech.Engng., Ass. Prof., 工学部, 助教授 (10170325)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Tateyuki Toyama Pref.Uhiv., Dept. Mech.Sys.Engng., Prof., 工学部, 教授 (20118665)
ADACHI Takashi saitama lnst.Tech., Dept.Mech.Engng., Prof., 工学部, 教授 (30118658)
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| Project Period (FY) |
1996 – 1997
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| Keywords | shock wave / reflection phenomena / unsteady reflection / formtion mechanism / tramsition wedge angle / weak shock wave |
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| Research Abstract |
Shock reflection phenomena over curved surfaces have been investigated both experimentally and theoretically. The models used in this experiment are ordinary circular cylindrical concave and convex wedges and step-like models which simulate the former. The step-like models were used to investigate the process of reflected wave formation over circular cylindrical wedges. The present experimental method by use of step-like models are dubbed method of multiple steps by our research group.
The reflected wave structure has been photographed with a schlieren apparatus. The formation mechanism of the reflected wave over circular cylindrical wedges is physically well understood by comparing it with shock reflection over step-like models. In particular, the reason why the reflected wave over a concave circular cylindrical wedge is very weak away fl.om the reflection point is elucidated. Moreover the structure and the formation mechanism of the so-called transitioned regular reflection (TRR) are illustrated in detail. By considering the behavior of the compression wave issued from the step, an analytical formula for the transition wedge angle is proposed and found in good agreement with thc experiment.
We were also interested in the effect of some parameters (initial wedge angle, incident shock Mach number and radius of curvature) over the transition wedge angle. The experiment has been performed to investigate such effects. When the initial wedge angle of the concave wedge increases, the analytical formula derived for zero initial wedge angle does not give the correct value. A theoretical method to calculate transition wedge angle was proposed and in good agreement with experiment. Comparison with another method shows this is a far better method for predicting the transition wedge angle.
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