Download or read book Experimental Investigation of Compressible Boundary Layers Under the Influence of Pressure Gradients written by Raymond C. Wier and published by . This book was released on 1996-12-01 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examined the effect of mild pressure gradients on the mean and turbulent flow of high-speed boundary layers. Three Mach numbers (1.7, 3.0 and 5.0) were investigated. Three pressure gradients were examined; a zero pressure gradient (ZPG), a favorable pressure gradient (FPG), and a combined pressure gradient (CPG). The CPG consisted of an adverse pressure gradient followed by a favorable pressure gradient. Conventional pressure probes, hot- wire and particle image velocimetry (PIV) were used to examine the flow. Measurement included mean velocity, velocity turbulence intensity, mass flux turbulence intensity and energy spectra. Instantaneous (10 nsec) Mie scattering flow visualizations were acquired. Qualitatively, the flow visualizations indicated that the turbulent flow structures were strongly affected by the pressure gradients. For the Mach 2,8 case, the PIV contours and the hot-wire profiles both indicated that the boundary layer thickness increased by 40% and decreased by 100% relative to the ZPG for the favorable and adverse pressure gradients, respectively. Further, the PIV and hot-wire data indicated that the axial turbulence intensity levels increased by 22% for the CPG and decreased by 25% for the FPG. The energy spectra data indicated that once a pressure gradient was applied (favorable or adverse) the low frequency energy increased followed by a rapid decay. Lastly, it was found that nominally 20 to 30 PIV images were sufficient for mean flow boundary layer velocities, but 93 images (the maximum recorded in this study) were insufficient to adequately resolve Reynolds shear stresses.

Download or read book An Experimental Investigation of the Compressible Turbulent Boundary Layer with a Favorable Pressure Gradient written by David L. Brott and published by . This book was released on 1969 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paper describes the results of a detailed experimental investigation of a two-dimensional turbulent boundary layer in a favorable pressure gradient where the free-stream Mach number varied from 3.8 to 4.6 and the ratio of wall to adiabatic-wall temperature has a nominal value of 0.82. Detailed profile measurements were made with pressure and temperature probes; skin friction was measured directly with a shear balance. The velocity- and temperature-profile results were compared with zero pressure gradient and incompressible results. The skin-friction data were correlated with momentum-thickness Reynolds number and pressure-gradient parameter. (Author).

Download or read book An Experimental Investigation of a Compressible Turbulent Boundary Layer Subjected to a Systematic Variation of Adverse Pressure Gradients written by Paul John Waltrup and published by . This book was released on 1971 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of the Effect of a Systematically Varied Adverse Pressure Gradient on the Growth of Turbulent Boundary Layers written by Joseph Alfred Schetz and published by . This book was released on 1960 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of Compressible Turbulent Boundary Layers in an Adverse Pressure Gradient with and Without Surface Curvature written by Jung-Hua Chou and published by . This book was released on 1982 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Documentation of Pressure Gradient and Reynolds Number Effects on Compressible Turbulent Boundary Layers written by and published by . This book was released on 1978 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Method for Predicting Compressible Turbulent Boundary Layers in Adverse Pressure Gradients written by Shimer Zane Pinckney and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of the Compressible Turbulent Boundary Layer with a Favorable Pressure Gradient written by David L. Brott and published by . This book was released on 1969 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paper describes the results of a detailed experimental investigation of a two-dimensional turbulent boundary layer in a favorable pressure gradient where the free-stream Mach number varied from 3.8 to 4.6 and the ratio of wall to adiabatic-wall temperature has a nominal value of 0.82. Detailed profile measurements were made with pressure and temperature probes; skin friction was measured directly with a shear balance. The velocity- and temperature-profile results were compared with zero pressure gradient and incompressible results. The skin-friction data were correlated with momentum-thickness Reynolds number and pressure-gradient parameter. (Author).

Download or read book Experimental Reynolds Analogy Factor for a Compressible Turbulent Boundary Layer with a Pressure Gradient written by Lionel Pasiuk and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was made of the effect of a favorable pressure gradient on the Reynolds analogy factor, K = 2St/C sub f, for a natural two-dimensional supersonic turbulent boundary layer in air. Integrated values of the skin friction coefficient and Stanton number were determined from experimental data. The results show that Colburn's value of K = Pr to the - 2/3 power, which was found empirically from zero pressure gradient data, is satisfactory for relating skin friction and heat transfer for the magnitudes of pressure gradients investigated. (Author).

Download or read book An Experimental Investigation of the Influence of Pressure Gradient and Free Stream Turbulence on Transition in the Boundary Layer on a Flat Plate written by Grant Keir and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of Upstream History Effects in Compressible Turbulent Boundary Layers written by David F. Gates and published by . This book was released on 1973 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes an experimental study of compressible turbulent boundary layers for which the upstream history was systematically varied. A series of experiments was conducted using both a supersonic half nozzle and a conventional flat plate for which the nozzle throat and flat plate leading edge can be temperature controlled. The supersonic nozzle provided a favorable upstream pressure gradient together with a controlled thermal history at the throat. The flat plate provided upstream temperature control with no pressure history. Velocity and temperature profile and heat-transfer measurements were made in a downstream region of zero-pressure-gradient and constant wall temperature. (Modified author abstract).

Download or read book An Experimental Study of the Receptivity of a Compressible Laminar Boundary Layer and the Effects on Stability and Receptivity of 2 D and 3 D Pressure Gradients written by and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Techniques have been developed to provide, for the first time, pure tone acoustic forcing with a wave packet having a particular wave vector and at instability wave frequencies for a supersonic boundary layer. Receptivity to this pure tone forcing has been studied, initially with continuous forcing and now with well defined wave packets. In the latter case precise measurements can now be made of the detailed response to the free-stream disturbance. The wave velocity and wave vector in the free-stream have been determined consistently. A preliminary finding from the wave packet experiments is that the boundary layer response is broadly in two parts; one which is a local forced response in phase with the free-stream forcing and the other which, at downstream locations, has larger amplitude, is growing with downstream distance and has a significant time delay compared with the first forced response. The explanation for this second wave packet and its relation to the first is not yet clear and is the present subject of detailed investigation. Once the data and an understanding are obtained with the present U + a wave forcing attention will be focused on U - a waves. It was found in 1, that the stream-wise wavelengths of the instability waves and the acoustic U - a free-stream fluctuations were closely matched and it was speculated that this played an important role in receptivity.

Download or read book Investigation of the Effect of Two Dimensional Cavities on Boundary Layers in an Adverse Pressure Gradient written by Richard J. Margason and published by . This book was released on 1996-03-01 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present investigation evaluated one aspect of the feasibility of the use of multiple cavities as an airfoil high-lift device. The effects of cavities on the boundary layer characteristics in several pressure gradients were determined experimentally and computationally. Experimentally, it was found that up to four cavities could be deployed with only a small change to the boundary layer profiles downstream of the cavities and without significantly modifying the resultant streamwise pressure distribution. From the computational results for both of the wind tunnel test section lengths used in the experimental investigation, it was found that a grid which provided a converged solution in less than a few hundred iterations was needed before a reasonable comparison with experimental data could obtained. It was also found for these converged solutions that the appropriate grid clustering and density as well as the cell size required for a satisfactory solution was not always apparent before comparing computational results with experimental data. Overall, the investigation results show that a multiple cavity high-lift concept may be feasible.

Download or read book An Investigation of the High Speed Turbulent Boundary Layer with Heat Transfer and Arbitrary Pressure Gradient Part 2 The Compressibility Transformation General Considerations written by and published by . This book was released on 1970 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the High Speed Turbulent Boundary Layer with Heat Transfer and Arbitrary Pressure Gradient The Compressibility transformation written by Constantino Economos and published by . This book was released on 1970 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report investigates the behavior of high speed turbulent boundary layer with heat transfer and streamwise pressure gradient.

Download or read book Compressible Turbulent Boundary Layers written by and published by . This book was released on 1969 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Critical Commentary on Mean Flow Data for Two dimensional Compressible Turbulent Boundary Layers written by Hans-Hermann Fernholz and published by . This book was released on 1980 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a discussion of mean flow profile data for compressible boundary layers. In AGARDograph 223, (Fernholz and Finley, 1977) the predecessor of this volume, data were presented for nominally two-dimensional flows for which mean flow profile data were available in tabular form. Data for 59 experimental boundary layer studies were given, with a brief introduction. Comment and discussion were reserved for this volume, AGARDograph 253. Suitable cross-references are given to relate the discussion in this volume to the earlier publication. The commentary in this volume includes discussion of the theroetical basis for interpretation of measurements, concepts from low-speed studies, interpretation of mean flow data with and without pressure gradient. The causes of normal pressure gradients are described, so as to allow an estimation of their magnitude, and their influence on boundary layer scale lengths. A third volume is planned in this series, which will include additional data, some of which is discussed here. This work was sponsored by the Fluid Dynamics Panel of AGARD. (Author).