Experimental and Numerical Studies on Vortical Flows Induced by Shock Wave Focusing over Parabolic Reflectors
博士 === 國立成功大學 === 航空太空工程學系 === 85 === The problem of a plane shock wave propagating in an air media over atwo-dimensional/axisymmetric parabolic reflectors is considered. Theshock wave after reflecting from the parabolic concave reflector formsa convergin...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
1997
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| Online Access: | http://ndltd.ncl.edu.tw/handle/59877377804938454098 |
| Summary: | 博士 === 國立成功大學 === 航空太空工程學系 === 85 === The problem of a plane shock wave propagating in an air media
over atwo-dimensional/axisymmetric parabolic reflectors is
considered. Theshock wave after reflecting from the parabolic
concave reflector formsa converging concave shock wave. The
converging cancave reflected shockwave will focus at later time
and results in a complicated flow fieldwith multiple vortices.
The focused shock wave can greatly magnify thepressure and the
temperature, and induce vortical flows. The purposeof this study
is to investigate the phenomenon of vortical flowsinduced by
shock wave focusing and to understand the mechanism of thevortex
formation through Experimental Fluid Dynamic (EFD) and
Computational Fluid Dynamic (CFD) method. The EFD technique is
toemploy a shock tube equipment to generate planar incident
shockwave, that reflects from parabolic reflector and focuses at
gasdynamicfocus. The color schlieren optical photography is used
to record theimages of the flow fields. The piezo-electric
pressure transducers areused to measure the dynamic pressures.
The implicit upwind TVD schemewith an improved flux limiter is
used to simulate the problem ofinterest. The real-gas-effect is
taken into account through a propercorrection of the specific
heat ratio of air. The implosion phenomenonis also investigated.
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