Download or read book Experimental Investigation of Turbulent Boundary Layer with Uniform Blowing at Moderate and High Reynolds Numbers written by Gazi Hasanuzzaman and published by Cuvillier Verlag. This book was released on 2022-01-18 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental investigation in turbulent boundary layer flows represents one of the canonical geometries of wall bounded shear flows. Utmost relevance of such experiments, however, is applied in the engineering applications in aerospace and marine industries. In particular, continuous effort is being imparted to explore the underlying physics of the flow in order to develop models for numerical tools and to achieve flow control. Flow control experiments have been widely investigated since 1930’s. Several flow control technique has been explored and have shown potential benefit. But the choice of control technique depends largely on the boundary condition and the type of application. Hence, friction drag of subsonic transport aircraft is intended to be reduced within the scope of this Ph. D. topic. Therefore, application of active control method such as microblowing effect in the incompressible, zero pressure gradient turbulent boundary layer was investigated. A series of experiments have been performed in two different wind tunnel facilities. Wind tunnel from Department of Aerodynamics and Fluid Mechanics (LAS) was used for the measurements for moderate Reynolds number range in co-operation with the wind tunnel from Laboratoire de M´ecanique de Feiret Lille for large Reynolds number range. Measurements are conducted with the help of state-of-the-art techniques such as Laser Doppler Anemometry, Particle Image Velocimetry and electronic pressure sensors.

Download or read book An Experimental Investigation of the Flow Structure of the Turbulent Boundary Layer written by Peter W. Runstadler and published by . This book was released on 1963 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: A combination of visual and quantitative measurements is presented, providing a physical picture of the turbulent boundary layer flow structure on a flat plate. The flow structure is shown to consist of three zones, each zone has a one to one correspondence to the well known regions of the u+, y+ mean velocity profile. A wall layer region is shown to exist below y+ = 10. An apparently fully turbulent region exists corresponding to the logarithmic ''law of the wall'' and the ''buffer'' region. An intermittent zone appears to agree closely with the ''wake'' deviation region. An entirely new result of the investigation is the delineation of the structure of the wall layer region. This region is shown to contain a relatively regular structure of low and high velocity fluid streaks alternating in the span direction, together with the ejection of low momentum fluid into the outer flow. Correlations are given for the rate of ejection and the streak spacing. A qualitative description of other features of the wall layer region and the character of the remainder of the boundary layer flow structure is presented. (Author).

Download or read book Preliminary Experimental Investigation of Effect of Free stream Turbulence on Turbulent Boundary layer Growth written by S. J. Kline and published by . This book was released on 1960 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Structure of High Reynolds Number Turbulent Boundary Layers written by James G.. Brasseur and published by . This book was released on 1994 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Performance Computing in Science and Engineering 19 written by Wolfgang E. Nagel and published by Springer Nature. This book was released on 2021-05-29 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2019. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.

Download or read book Experimental Investigation of the Effects of Viscosity on the Drag of Bodies of Revolution at a Mach Number of 1 5 written by Dean R. Chapman and published by . This book was released on 1947 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Tests were conducted to determine the effects of viscosity on the drag and base pressure characteristics of various bodies of revolution at a Mach number of 1.5. The models were tested both with smooth surfaces and with roughness added to evaluate the effects of Reynolds number for both laminar and turbulent boundary layers. The principal geometric variables investigated were after-body shape and length-diameter ratio. For most models, force tests and base pressure measurements were made over a range of Reynolds numbers, based on model length, from 0.6 million to 5.0 millions. Schlieren photographs were used to analyze the effects of viscosity on flow separation and shock-wave configuration near the base and to verify the condition of the boundary layer as deduced from force tests. The results are discussed and compared with theoretical calculations.

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 Vortex Generation in a Turbulent Boundary Layer Undergoing Adverse Pressure Gradient written by Victor Zakkay and published by . This book was released on 1972 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A High Lift Building Block Flow written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental evidence exists which suggests turbulent boundary layer relaminarization may play an important role in the inverse Reynolds number effect in high-lift systems. An experimental investigation of turbulent boundary layer relaminarization has been undertaken at the University of Notre Dame's Hessert Center for Aerospace Research in cooperation with NASA Dryden Flight Research Center. A wind tunnel facility has been constructed at the Hessert Center and relaminarization achieved. Preliminary evidence suggests the current predictive tools available are inadequate at determining the onset of relaminarization. In addition, an in-flight relaminarization experiment for the NASA Dryden FTF-II has been designed to explore relaminarization at Mach and Reynolds numbers more typical of commercial high-lift systems.Bourassa, Corey and Thomas, Flint O. and Nelson, Robert C.Armstrong Flight Research CenterMACH NUMBER; REYNOLDS NUMBER; TURBULENT BOUNDARY LAYER; WIND TUNNELS; PREDICTIONS; EXPERIMENTATION

Download or read book Turbulent Boundary Layer Experimental Heat Transfer with Blowing Suction and Favorable Pressure Gradient written by Stanford University. Thermosciences Division and published by . This book was released on 1969 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of the Influence of the Turbulent Boundary Layer on the Pressure Distribution Over a Rigid Two dimensional Wavy Wall written by Lado Muhlstein and published by . This book was released on 1971 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study on High Subsonic Turbulent Flow Incipient Separation written by Jain-Ming Wu and published by . This book was released on 1976 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: For flow over a two-dimensional ramp compression corner case, an experimental investigation to determine the incipient separation was carried out at Mach numbers between 0.55 and 0.9 and Reynolds numbers (based on undisturbed boundary layer thickness) between 350,000 and 690,000. Detailed surface pressure, pitot traversing and oil flow data were obtained for each ramp angle case. Two-dimensionality of the ramp compression corners was verified by the surface oil flow. A major finding of this study is that the incipient separation ramp angle is relatively independent of Mach number and Reynolds number within the range studied. The incipient separation ramp angle was found to be about 22.5 degrees.

Download or read book Examination of the Existing Data on the Heat Transfer of Turbulent Boundary Layers at Supersonic Speeds from the Point of View of Reynolds Analogy written by Alvin Seiff and published by . This book was released on 1954 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat-transfer data from four wind-tunnel experiments and two free-flight experiments with turbulent boundary layers have been examined to see whether or not they are well represented by the Reynolds analogy or a modification thereof. The heat-transfer results are put into the form of dimensionless Stanton numbers based on fluid properties at the outer edge of the boundary layer and are compared with skin-friction coefficients for the same Mach numbers and wall to free-stream temperature ratios as obtained from an interpolation of the existing skin-friction data. The effective Reynolds number is taken to be the length Reynolds number measured from the effective turbulent origin, a position which differs importantly from the leading edge of the test surface in some cases.

Download or read book An Experimental Investigation of Nozzle exit Boundary Layers of Highly Heated Free Jets written by Jan Lepicovsky and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of the effects of nozzle operating conditions on the development of nozzle-exit boundary layers of highly heated air free jets is reported in this paper. The total pressure measurements in the nozzle-exit boundary layer were obtained at a range of jet Mach numbers from 0.1 to 0.97 and jet total temperatures up to 900 K. The analysis of results shows that the nozzle-exit laminar boundary-layer development depends only on the nozzle-exit Reynolds number. For the nozzle-exit turbulent boundary layer, however, it appears that the effects of the jet total temperature on the boundary-layer integral characteristics are independent from the effect of the nozzle-exit Reynolds number. This surprising finding has not yet been reported. Further, laminar boundary-layer profiles were compared with the Pohlhausen solution for a flat-wall converging channel and an acceptable agreement was found only for low Reynolds numbers. For turbulent boundary layers, the dependence of the shape factor on relative Mach numbers at a distance of one momentum thickness from the nozzle wall resembles Spence's prediction. Finally, the calculated total pressure loss coefficient was found to depend on the nozzle-exit Reynolds number for the laminar nozzle-exit boundary layer, while for the turbulent exit boundary layer this coefficient appears to be constant.

Download or read book An Experimental Investigation of Regions of Separated Laminar Flow written by Donald E. Gault and published by . This book was released on 1955 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented from an investigation of regions of separated flow caused by separation of the laminar boundary layer (laminar-separation "bubbles"). The investigation was undertaken to obtain measurements which would define a large number of these bubbles for a wide range of Reynolds numbers and pressure gradients. In this manner, existing physical interpretations of the flow along a bubble could be studied in greater detail than in the past and, at the same time, it was hoped that the data would provide further insight into the conditions which control the occurrence and extent of a bubble.

Download or read book A Forward Facing Step Study written by Richard T. Driftmyer and published by . This book was released on 1973 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation involving a thick, adiabatic, naturally turbulent, two-dimensional boundary layer undergoing separation has been completed at the Naval Ordnance Laboratory (NOL). Forward facing steps (with attached end plates) were used to induce boundary-layer separation for the particular case where the step heights, h, were less than the boundary-layer thickness, delta. The tests were conducted at a free-stream Mach number of 4.9 with a range of unit Reynolds numbers varying from 0.8 x 10 to the 6th power per foot to 4.0 x 10 to the 6th power per foot. The pressure distributions measured in the separated region ahead of the steps were found to be functions of both Re sub delta and h/delta for the turbulent boundary-layer separation case where h

Download or read book Experimental Investigation of Heat Transfer Through Laminar and Turbulent Boundary Layers on a Cooled Flat Plate at a Mach Number of 2 4 written by Ellis G. Slack and published by . This book was released on 1952 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind-tunnel tests of the heat-transfer characteristics for laminar and turbulent boundary layers on a cooled flat plate were conducted at a Mach number of 2.4. Data were obtained for a Reynolds number range of 150.000 to 3,000.000 and for a surface-temperature range of -40 degrees F to 45 degrees F with recovery temperature of the order of 65 degrees F. The temperature-recovery factors agreed well with previous flat-plate reslts. The heat-transfer results were obtained with negative temperature gradients along the surface and, when related to the constant-surface-temperature case, were, in general, in good agreement with theory.