Investigation of Supersonic Boundary Layer Transition and Turbulent Structure PDF Download
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Author:
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Category :
Languages : en
Pages : 0
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Book Description
This final report describes the research progress made possible with the equipment purchased under this grant, and the manpower supplied by Princeton University as part of cost sharing.
Author:
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Category :
Languages : en
Pages : 0
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Book Description
This final report describes the research progress made possible with the equipment purchased under this grant, and the manpower supplied by Princeton University as part of cost sharing.
Author: Alexander J. Smits
Publisher:
ISBN:
Category : Rayleigh scattering
Languages : en
Pages : 40
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Author: William A. Cassels
Publisher:
ISBN:
Category : Aerodynamics, Supersonic
Languages : en
Pages : 76
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Book Description
Boundary-layer transition by the sublimation and impact-pressure techniques and force tests have been performed on three Haack-Adams bodies of revolution of fineness ratios 7, 10, and 13 at zero angle of attack for free-stream Mach numbers of 2.00, 2.75, and 4.63 and a range of Reynolds numbers based on model length of 6 to 15 X 10(to the 6 power) with and without a roughness strip. The grit method of inducing turbulence was found to provide for a nearly complete turbulent flow over the models at the lower Mach numbers and higher Reynolds numbers considered in this study while the amount of trip drag was less than 8 percent of the model drag with transition fixed. A method of interpreting sublimation data was discussed and used and the results compared well with the impact-pressure results.
Author: E. R. Van Driest
Publisher:
ISBN:
Category : Aerodynamics, Supersonic
Languages : en
Pages : 108
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Book Description
Experiments carried out in the 12-inch supersonic wind tunnel to investigate the effect of three dimensional roughness elements (spheres) on boundary-layer transition on a 10-degree (apex angle) cone without heat transfer are described. The local Mach number for these tests was 2.71. The data show clearly that the minimum (effective) size of trip required to bring transition to its lowest Reynolds number varies power of the distance from the apex of the cone to the trip. Use of available data at other Mach numbers indicates that the Mach number influence for effective tripping is taken into account by a simple expression. Some remarks concerning the roughness variation for transition on a blunt body are made. Finally, a general criterion is introduced which gives insight to the transition phenomenon and anticipates effects of external and internal disturbances, Mach number transfer.
Author: Alexander J. Smits
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 76
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Book Description
Author: Muhammad Farrukh Shahab
Publisher: LAP Lambert Academic Publishing
ISBN: 9783848415151
Category :
Languages : en
Pages : 228
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As a prerequisite for relevant model development and improvement of design methodologies for supersonic vehicles, this study aims at investigating the influence of wall heat-transfer and shock interaction on the turbulence structure of supersonic boundary layers. Incipient separation conditions and two different wall thermal boundary conditions (adiabatic and cold) are considered. The analysis focuses on the evolution of mean and turbulent flow properties along the interaction region and in the relaxation region downstream of the shock-system. The strong influence of the mean pressure gradient is quantified through the analysis of mean flow profiles and boundary layer integral parameters. The anisotropic amplification of turbulent quantities through the interaction region is characterized and the turbulent events associated with the modification of the turbulence structure of the perturbed boundary layer are identified. The mean and turbulent thermal fields are shown to be strongly modified by the wall cooling which significantly dampens more particularly the turbulent thermal quantities levels across the boundary layer.
Author: A. J. Laderman
Publisher:
ISBN:
Category :
Languages : en
Pages : 135
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Book Description
This report presents mean flow profiles across a two-dimensional, flat plate, compressible turbulent boundary layer. The mean flow properties were determined from pitot pressure and total temperature surveys carried out at three streamwise locations for wall to freestream total temperature ratios of 0.94 (adiabatic case), 0.714 and 0.54. All tests were conducted for a freestream Mach number of 3.0 with Reynolds number, based on momentum thickness, varying from 3200 to 4200. Although the outer two thirds of the viscous sublayer was probed, no evidence was found of a linear velocity gradient near the wall. However, the skin friction calculated using two conventional correlations were in good agreement with the trend of data. Furthermore, comparison of the velocity profile with Coles Law-of-the-Wake correlation indicated that the boundary is characteristic of a fully developed zero pressure gradient, flat plate flow. Results were in accord with those of other investigators for supersonic flows. In particular, the calculated eddy viscosity was in excellent agreement with the correlation derived by Maise and McDonald.
Author: Holger Babinsky
Publisher: Cambridge University Press
ISBN: 1139498649
Category : Technology & Engineering
Languages : en
Pages : 481
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Book Description
Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.
Author: John C. Adams
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 98
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Book Description
An analytical approach toward numerical calculation of the three-dimensional turbulent boundary layer on a sharp cone at incidence under supersonic and hypersonic flow conditions is presented. The theoretical model is based on implicit finite-difference integration of the governing three-dimensional turbulent boundary-layer equations in conjunction with a three-dimensional scalar eddy-viscosity model of turbulence. Comparison is made of present theory with detailed experimental measurements of the three-dimensional turbulent boundary-layer structure (velocity and temperature profiles), the surface streamline direction (obtained via an oil-flow technique) and surface heat-transfer rate.
Author: Henny Bottini
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
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Book Description
Turbulence onset within an initially laminar flow is one of the most common phenomenon in Fluid Mechanics, yet is an open field of research. This is due to the many and diverse causes that can trigger turbulence, which often add to each other, change their effect upon the flow velocity, and are difficult to single out in real-world situations. This is why laminar-toturbulent transition experiments have been and still are a fundamental tool for the researcher. This thesis work has addressed the study of turbulence onset in supersonic flows from an experimental point of view. Two test campaigns have been carried out each in a dedicated supersonic wind tunnel. The first aimed at tracking turbulence onset triggered by a single tetrahedral roughness element. It has been carried out in a multiple-Mach-number supersonic wind tunnel whose qualification campaign has been completed within this thesis work. Two roughness heights were tested, both for two Mach numbers, 1.6 and 2.3. The second test campaign has investigated the effects of an oblique shock wave impinging onto a Mach-2 transitional boundary layer. The transitional state of a boundary layer is that state during which the boundary layer passes from fully laminar to fully turbulent. This passage can be either induced or natural, and it was represented in this thesis work by the trigger wake and by the boundary layer flow downstream of the release point of an electric spark, respectively. Surface sensors, as thin-films and piezoelectric pressure transducers, were used to measure steady and unsteady highfrequency flow evolutions. Different wall temperatures were set for the thin-films insert as to allow the experimental estimation of the recovery temperature. Convective heat-flux trends have been extracted from the steady measurements, which, together with the recovery temperature trends, allowed the calculation of the Stanton number trends. All these quantities let to conclude on the general state of the boundary layer investigated in the first test campaign. The post-processing of the unsteady measurements yielded temperature and pressure fluctuations spectra and RMS streamwise evolutions, along with spectral time evolution at a given position. For the first test campaign, they allowed the characterization of the unsteadiness produced by the roughness within the supersonic boundary layer at different downstream locations. In so doing, they helped conclude on the state of the boundary layer, thus on the effectiveness of the roughness in triggering transition to turbulence. For the second test campaign, they allowed to single out the unsteady effects of the shock impinging downstream of the single roughness and downstream of the electric spark release point. In this way, differences in the shock effect between the roughness configuration and the clean-plate configuration have been highlighted, and the effects of different spark release frequencies compared.
