Download or read book Influence of Roughness and Blowing on Compressible Turbulent Boundary Layer Flow written by Robert L. P. Voisinet and published by . This book was released on 1979 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The determination of the relative and combined effects of surface roughness and mass transfer on turbulent boundary-layer development, and in particular, on skin-friction drag was the prime objective of this study. Wind-tunnel tests were conducted in the NSWC Boundary-Layer Channel at a freestream Mach number of 2.9. The thick nozzle-wall boundary layer in the facility was subjected to a systematic variation of surface roughness and mass transfer conditions. Boundary-layer pressure and temperature surveys were obtained and skin friction was measured directly using a skin-friction balance which had a provision for active blowing through the floating drag element. Data comparisons with skin-friction theories and law-of-the-wall velocity profile correlations are presented. (Author).
Download or read book Influence of Roughness and Blowing on Compressible Turbulent Boundary Layer Flow written by Robert L.P. Voisinet and published by . This book was released on 1979 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compressible Turbulent Skin Friction on Rough and Rough wavy Walls in Adiabatic Flow written by Daniel C. Reda and published by . This book was released on 1974 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental program was conducted to investigate effects of roughness, and roughness superimposed on single and/or multiple, shallow, periodic waveforms, on turbulent boundary-layer skin friction and velocity profile, in compressible, adiabatic flow. Test conditions were Mach number = 2.9 and Reynolds number/ft = 2 million to 8 million. The planar models included smooth, sand-grain, machined and molded surface finishes. Direct measurements of surface shear and Pitot/recovery temperature profiles were obtained. (Modified author abstract).
Download or read book The Influence of Surface Roughness on Supersonic High Reynolds Number Turbulent Boundary Layer Flow written by Robert M. Latin and published by . This book was released on 1998-03-01 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive study of rough-wall high speed (M=2.9) high Reynolds number (Re/m = 1.9. 10 to the 7th power) turbulent boundary layer flow was performed consisting of experimental, analytical, and numerical methods. Six wall topologies consisting of a smooth and five rough surfaces (two and three dimensional machined roughness plates; and 80, 36, and 20 grit sand-grain roughened plates) were studied. A confocal laser scan microscope was used to measure the topography of the sand grain roughnesses. The experimental measurement techniques included a convention Pitot pressure probe, laser Doppler velocimetry, hot wire anemometry; color schlieren and laser sheet Mie scattering images. Mean measurements included velocity, Mach number, density, and mass flux. Turbulent measurements included velocity and mass flux turbulence intensities, kinematic Reynolds shear stress, compressible Reynolds shear stress in two planes, and the traverse apparent mass flux. Kinematic turbulent flow statistical properties were found to scale by local mean quantities and displayed a weak dependence on surface roughness. Turbulent flow statistical properties with the explicit appearance of density did not scale by local mean quantities, and had a strong linear dependence on roughness. Surface roughness also had a significant effect on the flow structure size, angles, and energy spectra. A theoretical analysis was performed and a new integral method for the estimation of skin friction was developed. The skin friction estimates were within 4% of compressible semi-empirical relations. A numerical study was performed which used a parabolized Navier Stokes solver with two algebraic turbulence models and the Rotta model for surface roughness. A new method for the estimation of momentum loss improved the numerical flow predictability.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Approximate Formulas for the Computation of Turbulent Boundary layer Momentum Thicknesses in Compressible Flows written by Neal Tetervin and published by . This book was released on 1946 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Approximate formulas for the computation of the momentum thicknesses of turbulent boundary layers on two-dimensional bodies, on bodies of revolution at zero angle of attack, and on the inner surfaces of round channels all in compressible flow are given in the form of integrals that can be conveniently computed. The formulas involve the assumptions that the momentum thickness may be computed by use of a boundary-layer velocity profile which is fixed and that skin-friction formulas for flat plates may be used in the computation of boundary-layer thicknesses in flow with pressure gradients. The effect of density changes on the ration of the displacement thickness to the momentum thickness of the boundary layer is taken into account. Use is made of the experimental finding that the skin-friction coefficient for turbulent flow is independent of Mach number. The computations indicated that the effect of density changes on the momentum thickness in flows with pressure gradients is small for subsonic flows.
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 Handbook of Heat Transfer written by Warren M. Rohsenow and published by McGraw-Hill. This book was released on 1998-05-22 with total page 1528 pages. Available in PDF, EPUB and Kindle. Book excerpt: This wholly revised edition of a classic handbook reference, written by some of the most eminent practitioners in the field, is designed to be your all-in-one source book on heat transfer issues and problem-solving. It includes the latest advances in the field, as well as covering subjects from microscale heat transfer to thermophysical properties of new refrigerants. An invaluable guide to this most crucial factor in virtually every industrial and environmental process.
Download or read book The Turbulent Boundary Layer written by Stanford University. Thermosciences Division. Thermosciences Division and published by . This book was released on 1975 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The turbulent boundary on a deterministic rough wall has been examined for the cases of isothermal and non-isothermal, zero pressure gradient flows with and without transpiration. Both the transitionally rough and the fully rough.
Download or read book Handbook of Heat Transfer Fundamentals written by Warren M. Rohsenow and published by McGraw-Hill Companies. This book was released on 1985 with total page 1442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Perspectives in Turbulence Studies written by Hans U. Meier and published by Springer. This book was released on 2012-01-10 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present volume entitled "Perspectives in Turbulence Stud ies" is dedicated to Dr. Ing. E. h. Julius C. Rotta in honour of his 75th birthday. J. C. Rotta, born on January 1, 1912, started his outstanding career in an unusual way, namely in a drawing office (1928 - 1931). At the same time he - as a purely self taught perso- took a correspondence course in airplane construction. From 1934 to 1945 he worked in the aircraft industry on different subjects in the fields of flight mechanics, structures, air craft design, and aerodynamics. In 1945 he moved to Gottingen and worked from that time at the Aerodynamische Versuchsanstalt (AVA, now DFVLR) and the Max-Planck-Institut fur Stromungsforschung (1947-1958), interrupted only by a stay in the U. S. at the Glenn L. Martin Company (1954 - 1955) and a visiting professorship at the Laval University in Quebec, Canada (1956). Already during his activities in industry, Dr. Rotta discovered his special liking for aerodynamics. In Gottingen, he was attracted by Ludwig Prandtl's discussions about problems associated with turbulence and in particular his new contribution to fully developed turbulence, published in 1945. At that time, W. Heisenberg and C. F. v. Weizacker pub lished their results on the energy spectra of isotropic turbu lence at large wave numbers. Since that time his main research interest in reasearch has been in turbulence problems.
Download or read book Effects of Unit Reynolds Number Nose Bluntness and Roughness on Boundary Layer Transition written by J. Leith Potter and published by . This book was released on 1960 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Condtions encountered in the high Mach number flow regime are show to profoundly affect the longitudinal extent of the boundary layer from beginning to end of transition, the distribution of fluctuation energy in the laminar layer, and effectiveness of surface roughness in promoting transition. A critical layer of intense local energy fluctuations was found at all Mach numbers studied. The existence of such a critical layer is predicted by stability theory. Hot-wire surveys of the laminar, transitional, and turbulent boundary layers are presented to illustrate the critical layer in laminar flow and subsequent development into the transition process. The relation between boundary layer transition on flat plates and cones in supersonic flow is explored and a process for correcting data to account for leading edge bluntness is devised. On the basis of a comparison of data corrected for the effects of leading edge geometry, it is shown that the Reynolds umber of transition on a cone is three times that on a vanishingly thin flate plate. Close agreement between data from various wind tunnels is demonstrated. Study of the effect of finite leading edges yields significant illustrations of the influence of unit Reynolds number on boundary layer transition. A correlation of the effects of surface roughness on transition is achieved. This treatment includes two- and three-dimensional roughness in both subsonic and supersonic streams. At this time only zero pressure gradients have been studied. The entire range of movement of transition from its position with no roughness up to its reaching the roughness element is describable by the procedure give. Examples of application of the correlation results show excellent agreement with experimental data from a variety of sources. Implications concerning tripping hypersonic boundary layers are discussed.
Download or read book Handbook of Single Phase Convective Heat Transfer written by Sadik Kakaç and published by Wiley-Interscience. This book was released on 1987-11-03 with total page 1268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Very Good,No Highlights or Markup,all pages are intact.
Download or read book AIAA 86 0251 AIAA 86 0298 written by and published by . This book was released on 1986 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Boundary Layer Flows written by Vallampati Ramachandra Prasad and published by BoD – Books on Demand. This book was released on 2023-02-22 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of boundary layer flows, including laminar and turbulent flows. Chapters discuss such topics as the nature of transition, the effect of two-dimensional and isolated roughness on laminar flow, and progress in the design of low-drag airfoils. They also present theoretical and experimental results in boundary layer flows and discuss directions for future research.
Download or read book A Proof of Concept Experiment for Reducing Skin Friction by Using a Micro Blowing Technique written by Danny P. Hwang and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
