1993 Fiscal Year Final Research Report Summary
Interdisciplinary approach to high Reynolds number turbulence
| Project/Area Number |
03302027
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Aerospace engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
TSUGE Shunichi Institute of Engineering Mechanics, University of Tsukuba, Professor, 構造工学系, 教授 (50133020)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIKAWA N. Faculty of Engineering, Toyohashi University of Technology, Associate Professor, 工学部, 助教授 (60135423)
MURAKAMI M. Institute of Engineering Mechanics, University of Tsukuba, Associate Professor, 構造工学系, 助教授 (40111588)
INOUE O. Institute of Fluid Science, Tohoku University, Professor, 流体科学研究所, 教授 (00107476)
ASOU S. Faculty of Engineering, University of Tsukuba, Associate Professor, 工学部, 助教授 (40150495)
AIHARA Y. Faculty of Engineering, University of Tokyo, Professor, 工学部, 教授 (90011072)
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| Project Period (FY) |
1991 – 1993
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| Keywords | High Reynolds number / turbulence / modeling / CFD / pulse jet / Gorter vortex / super-fluid / shock wave |
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| Research Abstract |
(1)THEORY
Multi-point fluctuation-correlation equations of the statistical turbulence theory are separated into single-point equations, thereby made applicable to turbulent flows of practical interest. The solitary-wave solution of the equation is obtained for incompressible mixing layrs and turbulent premixed flames. Turbulence intensity, Reynolds' stress and turbulent flame speed are obtained from this solution without having recourse to any empirical constants, and in good agreement with existing experiments(Tsuge). Absolute and convective instabilities of waves with free surface and convection velocity are discussed. Stability limit of spatially periodic flow is obtained using the Floquet theorem(Kyotoh).
(2)CFD
High Reynolds number mixing layr is dealt with using vortex method(incompressible) and finite volume method (compressible). Effects due to compressivility and a novel active control device of turbulent boundary layr are discussed(Inoue). Mumerical prediction of unsteady heatin
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g caused by wall-reflected shock waves is made using 2-D thin layr Navier-Stokes formalism(Asou). Algebraic RNG model is improved to make it applicable to Garabedian-Korn profile and the result shows good agreement with Baldwin-Lomax model(Nakamura). It is necessary to incorporate nonequilibrium effect on turbulence modeling in computing vortex shedding in the nose-down posture of a wing(Fujii). Analysis of pulse jet combution shows considerable distortion of the flame surface due to baroclinic interaction with compression waves emerging from flame itself(Hayashi). A method of third order multi-directional upwind finite difference scheme is proposed. It is applied to high Reynolds number unsteady flow with complex geometry with satisfactory accuracy(Kuwahara).
(3)EXPERIMENTS
Mechanism of flame-holding in the presence of strong shear and flame-stretching is identified(Niioka). Transition of flat/concave-plate boundary layrs are investigated, and it is found that there is a feed back system between longitudinal vortices and outer-layr turbulent spots(flat-plate), also that there are three types of turbulence mode(Gortler vortices)(Aihara). A four-time tracking device is developed to materialize algorism to compute flow velocity by controlling stroboscopic emission in the image processing to 6msec(Nishikawa). Evidence of transition to turbulence and T_1-T_2 transition in super-fluid He is clarified through the laser-doppler measurement of thermal counter flow jets(Murakami). Initial stage of coherent structure in the mixing layr is shown to persist over a long streamwise range(Suzuki). High resolution measurement devise is developed and is applied to measuring CO_2 concentration in turbulent jel(Rayleigh scattering)and OH fluorescence in flames(LIF)(YOSHIKAWA). Interactions of utrbulent boundary layr with 3-D shock waves generated by sharp/blunt fins also with bow shock waves are investigated. It is observed that the boundary layr repeats secondary detach/attach-ment with frequencies of several kHz(Asou). Less
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