| Interaction of Chemistry, Turbulence, and Shock Waves in Hypervelocity Flow |
MAY 94 |
67 pages |
| Authors:
G. V. Candler; P. E. Dimotakis; H. G. Hornung; A. Leonard; D. I. Meiron; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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 | Significant progress was made during the first year of an interdisciplinary experimental, numerical and theoretical program to extend the state of knowledge and understanding of the effects of chemical reactions in hypervelocity flows. The program addressed the key problems in aerothermochiemistry that arise from interactions between the three strongly nonlinear effects: Compressibility; vorticity; and chemistry. Important new results included: Experimental data on the effect of enthalpy on transition in hypervelocity ... |
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| Image Correlation Velocimetry |
01 FEB 93 |
32 pages |
| Authors:
P. T. Tokumaru; P. E. Dimotakis; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| This paper focuses on the correlation of two successive scalar images for the purpose of measuring imaged fluid motions. A method is presented for deforming, or transforming, one image to another. Taylor series expansions of the Lagrangian displacement field are used, in conjunction with an integral form of the equations of motion, to approximate this transformation. The proposed method locally correlates images for displacements, rotations, deformations, and higher order displacement ... |
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| Unsteady and Separated Flows |
30 NOV 88 |
22 pages |
| Authors:
P. E. Dimotakis; A. Leonard; A. Roshko; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| A computer controlled system for the X- carriage on the Tow Tank has been installed. A force balance for measuring dynamic forces on models carried by the carriage has been built and installed. Initial measurements of such forces have been obtained on a flat-plate airfoil at various angles of attack. Optical and computer components have been assembled and integrated into a system for acquiring and processing streakline images of fluorescent ... |
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| Active Feedback Interaction with a Shear Layer |
15 AUG 87 |
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| Authors:
P. E. Dimotakis; M. M. Koochesfahani; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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 | Study of the open-loop forcing of shear layer by a pitching airfoil resulted in three major findings: 1) It is possible to induce very large changes in the shear layer growth rate downstream of the disturbance location, while leaving the portion of the layer between the splitter plate and the disturbance location essentially unaffected; 2) Upstream forcing can be used as a means to modify the shear layer in the ... |
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| Chemical Reactions in Turbulent Mixing Flows |
01 JUN 87 |
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| Authors:
P. E. Dimotakis; J. E. Broadwell; A. Leonard; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| Work continues primarily in gas phase turbulent mixing amd chemical reactions with extensions to compressible (supersonic) shear layers. In the gas phase shear layer work, investigations concentrate on subsonic shear layer free stream density ratio effects, and a design effort in support of the planned extension of the hydrogen-fluorine shear flow facility to supersonic flows. In jet flows, measurements of gas phase jet mixing, using laser Rayleigh scattering techniques developed ... |
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| Instrumentation for Turbulent Reacting Flows |
23 APR 87 |
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| Authors:
P. E. Dimotakis; D. B. Lang; R. C. Miake-Lye; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| The design and technical capabilities of the following systems are described: (1) Copper Vapor Laser pulsed light source with spatial filter and collimator.(2) Proximity focussed diode intensified linear CCD camera. (3) High speed multiplexed Analog to Digital Conversion system. (4) Monochromator system for point or line imaging of chemiluminescence. This instrumentation has been assembled to exploit several nonintrusive optical techniques to make measurements in a wide range of turbulent flows. ... |
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| Active Feedback Interaction with a Shear Layer |
30 JUN 86 |
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| Authors:
P. E. Dimotakis; M. M. Koochesfahani; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| Work continues on the characterization of the effects of a pitching airfoil on the shear layer structure and growth under open loop forcing. We have shown that locally introduced disturbances can induce significant changes in the growth of the shear layer mixing zone. A separate investigation into the structure of the wake of an oscillating airfoil in a steady, uniform free stream revealed the existence of an axial flow along ... |
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| Chemical Reactions in Turbulent Mixing Flows |
15 JUN 86 |
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| Authors:
P. E. Dimotakis; J. E. Broadwell; A. Leonard; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| Work is continuing primarily in gas phase turbulent mixing and chemical reactions. The liquid phase work to date is in its final stages of being analyzed and documented for dissemination in the form of archival publications. In the gas phase shear layer work, investigations are concentrating on shear layer free stream density ratio effects, finite kinetic rate (Damkohler number) effects, and a design effort in support of the planned extension ... |
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| Chemical Reactions in Turbulent Mixing Flows |
10 APR 86 |
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| Authors:
H. W. Liepmann; J. E. Broadwell; P. E. Dimotakis; CALIFORNIA INST OF TECH PASADENA
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| Work is continuing in both gas phase and liquid phase turbulent mixing and chemical reactions. In the gas phase shear layer work, our investigations are concentrating on shear layer free stream density ratio effects, finite kinetic rate (Damkohler number) effects, and heat release effects the latter up to a temperature rise in the combustion zone of the order of 1,000K. In jet flows, the development of laser Rayleigh scattering techniques ... |
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| Chemical Reactions in Turbulent Mixing Flows. Revision |
02 AUG 1983 |
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| Authors:
H. W. Liepmann; J. E. Broadwell; P. E. Dimotakis; A. Roshko; CALIFORNIA INST OF TECH PASADENA
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| Work under this contract has proceeded along three main lines, an experimental program covering low heat release combustion of hydrogen and fluorine, and chemically reacting turbulent shear layers and jets in water, a theoretical model development program whose aim is to provide alternatives to gradient diffusion transport models, and a diagnostics development parallel program to advance the state-of-the-art in experimental techniques, as dictated by our main experimental effort. Substantial progress ... |
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| Chemically Reacting Turbulent Shear Layers |
JAN 1983 |
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| Authors:
M. M. Koochesfahani; P. E. Dimotakis; J. E. Broadwell; CALIFORNIA INST OF TECH PASADENA
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| An experimental investigation of entrainment, mixing and chemical reactions in a plane shear layer has been performed using laser induced fluorescence techniques. Results indicate that the reactants mix on a molecular level and react at a composition that is nearly uniform across the width of the layer. The composition of the mixed fluid is found to be asymmetric, with an excess of high speed fluid, suggesting that entrainment into the ... |
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| Chemical Reactions in Turbulent Mixing. |
19 JUL 1979 |
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| Authors:
H. W. Liepmann; G. L. Brown; P. E. Dimotakis; F. E. Marble; A. Roshko; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
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| The more important results and developments achieved as a direct result of this contract are as follows: A model for the calculation of turbulent flows was constructed which incorporates effects of Reynolds stress relaxation with the generation or destruction of turbulent energy by rotation. The model was verified by comparison with experiment. It was then used to predict the properties of isolated turbulent vortices and applied to the turbulent mixing ... |
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