Download or read book An Experimental Study of Turbulence in a Driven Vortex written by Colman duP. Donaldson and published by . This book was released on 1964 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements have been made at two rotational speeds of the mean motion and turbulence levels within a shallow vortex chamber that has a rotating porous wall as an outer boundary. Very nominal levels of turbulence (2 to 3 per cent) were observed on the central plane of these vortices while a significant portion of the mass flow through the vortex was observed to pass through the end wall boundary layers. A fairly high level of turbulence was then introduced into this vortex chamber by means of a grid of axially aligned bars at the outer rim of the vortex. This high level of turbulence was observed to decay rapidly to a relative level of intensity of about 6 percent, indicating that for tangential Reynolds numbers up to at least 100000, the flow with a driven vortex is stable with respect to the introduction of turbulence. The results obtained corroborate Kendall's findings, namely that the primary cause of the degradation of the performance of a confined vortex is the leakage of mass flux through the boundary layers on the end walls of the vortex chamber. (Author).
Download or read book An Experimental Study of Vortex Flow and Turbulence in Concentric and Eccentric Annuli written by J. H. Vohr and published by . This book was released on 1964 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented for an experimental study of Taylor vortices and turbulence in the flow between a rotating inner cylinder and both concentric and eccentric stationary outer cylinders. The results include: 1). measurement of the critical speed for onset of Taylor vortices as function of the eccentricity of the cylinders, 2). visual study of the flow up to a Reynolds number of 40,000, 3). measurement of the friction factor for the flow up to a Reynolds number of number of 40,000, 4). study of the effect of axial flow on the critical speed for onset of Taylor vortices. 5). preparation of design charts for calculating friction loss in concentric and eccentric journal bearings, operating in super-laminar flow regime.--Author.
Download or read book Liutex and Its Applications in Turbulence Research written by Chaoqun Liu and published by Academic Press. This book was released on 2020-10-29 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liutex and Its Applications in Turbulence Research reviews the history of vortex definition, provides an accurate mathematical definition of vortices, and explains their applications in flow transition, turbulent flow, flow control, and turbulent flow experiments. The book explains the term "Rortex" as a mathematically defined rigid rotation of fluids or vortex, which could help solve many longstanding problems in turbulence research. The accurate mathematical definition of the vortex is important in a range of industrial contexts, including aerospace, turbine machinery, combustion, and electronic cooling systems, so there are many areas of research that can benefit from the innovations described here. This book provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence. Important theory and methodologies used for developing these laws are described in detail, including: the classification of the conventional turbulent boundary layer concept based on proper velocity scaling; the methodology for identification of the scales of velocity, temperature, and length needed to establish the law; and the discovery, proof, and strict validations of the laws, with both Reynolds and Prandtl number independency properties using DNS data. The establishment of these statistical laws is important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence. Provides an accurate mathematical definition of vortices Provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence Explains the term “Rortex as a mathematically defined rigid rotation of fluids or vortex Covers the statistical laws important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence
Download or read book Quantized Vortex Dynamics and Superfluid Turbulence written by C.F. Barenghi and published by Springer. This book was released on 2008-01-11 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book springs from the programme Quantized Vortex Dynamics and Sup- ?uid Turbulence held at the Isaac Newton Institute for Mathematical Sciences (University of Cambridge) in August 2000. What motivated the programme was the recognition that two recent developments have moved the study of qu- tized vorticity, traditionally carried out within the low-temperature physics and condensed-matter physics communities, into a new era. The ?rst development is the increasing contact with classical ?uid dynamics and its ideas and methods. For example, some current experiments with - lium II now deal with very classical issues, such as the measurement of velocity spectra and turbulence decay rates. The evidence from these experiments and many others is that super?uid turbulence and classical turbulence share many features. The challenge is now to explain these similarities and explore the time scales and length scales over which they hold true. The observed classical aspects have also attracted attention to the role played by the ?ow of the normal ?uid, which was somewhat neglected in the past because of the lack of direct ?ow visualization. Increased computing power is also making it possible to study the coupled motion of super?uid vortices and normal ?uids. Another contact with classical physics arises through the interest in the study of super?uid vortex - connections. Reconnections have been studied for some time in the contexts of classical ?uid dynamics and magneto-hydrodynamics (MHD), and it is useful to learn from the experience acquired in other ?elds.
Download or read book An Experimental Study of a Turbulent Vortex Ring written by Ari Glezer and published by . This book was released on 1981 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Velocity Profiles in a Decaying Turbulent Vortex written by Hugh Russell Whiteley and published by . This book was released on 1962 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Investigations of Three dimensional Viscous Vortex Flows written by Coleman duP. Donaldson and published by . This book was released on 1963 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research efforts carried out at ARAP during the past five years in the field of viscous vortex motions are summarized. The work cited constitutes a rather extensive program of theo retical and experimental studies of vortex mo tions in general and of three-dimensional laminar and turbulent incompressible driven vortices in particular. The theoretical studies fall into three general categories; the first and most important comprising velocity distributions for steady laminar motion, the second dealing with unsteady velocity characteristics, and the third treating temperature distributions for the steady motions first considered. An evaluation and discussion of the effects of turbulence in real flows of the general type under consideration is included. The work performed and the results and conclusions reached in each of the areas of study already mentioned are discussed. (Author).
Download or read book NASA Technical Note written by and published by . This book was released on 1965 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Angular momentum transport and pattern formation in medium and wide gap turbulent Taylor Couette flow written by Andreas Froitzheim and published by Cuvillier Verlag. This book was released on 2019-08-26 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent Taylor-Couette flow, where the fluid is confined by two coaxial and independently rotating cylinders, is experimentally investigated within this thesis for medium and wide gaps. To reveal the influence of flow patterns on the angular momentum transport, direct torque measurements, flow visualizations and particle image velocimetry are performed in two different facilities. For the largely unexplored radius ratio regime of η = 0.357, the directly measured torque features a transition as a function of shear, which is connected to the capacity of the outer cylinder to emit small-scale plumes. When the cylinders rotate slightly in counter-direction, a maximum in torque occurs at μmax = -0.123, which is induced by the formation of large-scale Taylor vortices. The contribution of these vortices to the overall momentum transport clearly exceeds the contribution of the turbulent fluctuations for η = 0.5. Furthermore, the large-scale Taylor rolls are driven by small-scale plumes and feature azimuthally traveling waves for η = 0.714. Accordingly, the angular momentum transport in medium and wide-gap turbulent Taylor-Couette flow is determined by the interaction of turbulence and flow patterns of different scales.
Download or read book An Experimental Study of Turbulent Vortex Rings Using Particle Image Velocimetry written by L. Gan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Proceedings written by and published by . This book was released on 1965 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation Into the Effects of Turbulence on Vortex Shedding written by Richard W. Nanes and published by . This book was released on 1967 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report Jet Propulsion Laboratory California Institute of Technology written by Jet Propulsion Laboratory (U.S.) and published by . This book was released on 1966 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Source and Evolution of Turbulence in Trailing Vortex Pairs written by Christine M. Vogel and published by . This book was released on 1995 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AN EXPERIMENTAL STUDY OF VORTEX FLOW FOR APPLICATION TO GAS PHASE FISSION HEATING written by and published by . This book was released on 1960 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation into the gas dynamics of a jet-driven vortex tube for application of a cavity nuclear reactor to rocket propulsion has shown that viscous retardation of the vortex motion is severe, because of a high level of turbulence near the periphery. Based on the experience gained in this study, it is estimated that the achievement of vortex strengths sufficient for practical application will require the use of small diameter tubes with appreciable expenditure of power for recirculation of the gas. The effect of the high degree of turbulence on the separation process near the periphery remains to be determined. The independent variables which were found to influence the vortex strength significantly for a given gas and temperature condition are the tube diameter, the mass flow rate per unit tube length, the injection velocity, and the wall pressure. Estimates of the degree of turbulence in vortex flow have been made from data on the variation in tangential velocity with radius. Virtual (total) viscosities near the periphery ranged from 30 to 700 times the molecular viscosity for tangential Reynolds numbers of from 4 x 10/sup 4/ to 2 x l0/sup 6/. Measurements of the position of the mole- fraction peak for separation of helium and a heavy vapor agreed with the theory for laminar flow. This suggests that near the center of the vortex tube where the peak developed the radial density gradient was sufficiently strong to suppress turbulence. It is concluded that the vortex reactor concept appears promising for application to nuclear rocket propulsion provided a satisfactory method can be devised for recirculation of the large excess mass flow required to maintain the vortex strength, and if turbulence does not appreciably limit the separation process. A separation experiment at elevated temperature appears to be the next logical step in the research program. (auth).
