Download or read book Experimental Study of Natural and Forced Instabilities and Transition of a Rotating disk Boundary layer Flow written by Muhammad Ehtisham Siddiqui and published by . This book was released on 2011 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation concerns experimental work on the instability and transition of the rotating-disk boundary-layer flow. In the case of the natural flow (i.e. without forcing), measurements of mean-flow profiles, frequency spectra and phase-locked averages of the velocity time series allow us to distinguish different flow regimes as a function of nondimensional distance, R, from the disk axis. As R increases, the mean-velocity profiles initially follow the von Kármán solution. At higher R, departures arise and increase with R. These departures are due to the spatial growth of boundary-layer instability modes (cross-flow vortices), whose radial growth rates are found to match linear-theory predictions. The flow becomes transitional at R ≈ 530 and fully turbulent by R ≈ 600. The profiles in the fully turbulent region follow the log law of turbulent boundary layers and the velocity spectra exhibit Kolmogorov-type power laws. To study the response to forcing, an experimental apparatus has been designed which allows the excitation of stationary (in thelaboratory frame of reference) disturbances or disturbances which rotate with a frequency which can be varied independently of the disk rotation rate. The flow response to both types of forcing and two forcing-element geometries was studied. Stationary forcing produces a wake which decays with distance from the element, in agreement with theory. Forcing due to rotating elements can generate growing wavepacket-like disturbances, which although nonlinear, follow trajectories close to linear-theory predictions.
Download or read book Experimental Investigation of Flow Over a Rotating Disk written by Dr. Muhammad Ehtisham Siddiqui and published by LAP Lambert Academic Publishing. This book was released on 2011-08 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the experimental study of the rotating-disk boundary-layer flow. In the case of the natural flow, different flow regimes are identified as a function of nondimensional distance, R, from the disk axis. Mean-velocity profiles initially follow the von Karman solution. At higher R, departures arise and increase with R, which are due to the spatial growth of boundary-layer instability modes, whose radial growth rates are found to match linear-theory predictions. The profiles in the fully turbulent region follow the turbulent log law and the velocity spectra exhibit Kolmogorov-type power laws. To study the response to forcing, a setup has been designed which allows the excitation of stationary (in the lab frame) disturbances or disturbances which rotate with a frequency independently of the disk frequency. The flow response to both types of forcing and two forcing element geometries was studied. Stationary forcing produces a wake which decays with distance from the element, in agreement with theory. Forcing due to rotating elements can generate growing wavepacket-like disturbances, which although nonlinear, follow trajectories close to linear-theory predictions.
Download or read book Modeling Atmospheric and Oceanic Flows written by Thomas von Larcher and published by John Wiley & Sons. This book was released on 2014-10-30 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling Atmospheric and Oceanic Flows: Insights from Laboratory Experiments and Numerical Simulations provides a broad overview of recent progress in using laboratory experiments and numerical simulations to model atmospheric and oceanic fluid motions. This volume not only surveys novel research topics in laboratory experimentation, but also highlights recent developments in the corresponding computational simulations. As computing power grows exponentially and better numerical codes are developed, the interplay between numerical simulations and laboratory experiments is gaining paramount importance within the scientific community. The lessons learnt from the laboratory–model comparisons in this volume will act as a source of inspiration for the next generation of experiments and simulations. Volume highlights include: Topics pertaining to atmospheric science, climate physics, physical oceanography, marine geology and geophysics Overview of the most advanced experimental and computational research in geophysics Recent developments in numerical simulations of atmospheric and oceanic fluid motion Unique comparative analysis of the experimental and numerical approaches to modeling fluid flow Modeling Atmospheric and Oceanic Flows will be a valuable resource for graduate students, researchers, and professionals in the fields of geophysics, atmospheric sciences, oceanography, climate science, hydrology, and experimental geosciences.
Download or read book Instability and Transition in Rotating Disk Flow written by and published by . This book was released on 1981 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Past Highly Compliant Boundaries and in Collapsible Tubes written by Peter W. Carpenter and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: The IUTAM Symposium on Flow in Collapsible Tubes and Past Other Highly Compliant Boundaries was held on 26-30 March, 2001, at the University of Warwick. As this was the first scientific meeting of its kind we considered it important to mark the occasion by producing a book. Accordingly, at the end of the Symposium the Scientific Committee met to discuss the most appropriate format for the book. We wished to avoid the format of the conventional conference book consisting of a large number of short articles of varying quality. It was agreed that instead we should produce a limited number of rigorously refereed and edited articles by selected participants who would aim to sum up the state of the art in their particular research area. The outcome is the present book. Peter W. Ca rpenter, Warwick Timothy J. Pedley, Cambridge May, 2002. VB SCIENTIFIC COMMITTEE Co-Chair: P.W. Carpenter, Engineering, Warwiek, UK Co-Chair: TJ. Pedley, DAMTP, Cambridge, UK V.V. Babenko, Hydromechanics, Kiev, Ukraine R. Bannasch, Bionik & Evolutionstechnik, TU Berlin, Germany C.D. Bertram, Biomedical Engineering, New South Wales, Australia M. Gad-el-Hak, Aerospace & Mechanical Engineering, Notre Dame, USA J.B. Grotberg, Biomedical Engineering, Michigan, USA. R.D. Kamm, Mechanical Engineering, MIT, USA Y. Matsuzaki, Aerospace Engineering, N agoya, Japan P.K. Sen, Applied Mechanics, IIT Delhi, India L. van Wijngaarden, Twente, Netherlands K-S. Yeo, Mechanical Engineering, NU Singapore.
Download or read book Modelling of Convective Heat and Mass Transfer in Rotating Flows written by Igor V. Shevchuk and published by Springer. This book was released on 2015-07-24 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents results of the analytical and numerical modeling of convective heat and mass transfer in different rotating flows caused by (i) system rotation, (ii) swirl flows due to swirl generators, and (iii) surface curvature in turns and bends. Volume forces (i.e. centrifugal and Coriolis forces), which influence the flow pattern, emerge in all of these rotating flows. The main part of this work deals with rotating flows caused by system rotation, which includes several rotating-disk configurations and straight pipes rotating about a parallel axis. Swirl flows are studied in some of the configurations mentioned above. Curvilinear flows are investigated in different geometries of two-pass ribbed and smooth channels with 180° bends. The author demonstrates that the complex phenomena of fluid flow and convective heat transfer in rotating flows can be successfully simulated using not only the universal CFD methodology, but in certain cases by means of the integral methods, self-similar and analytical solutions. The book will be a valuable read for research experts and practitioners in the field of heat and mass transfer.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 28th AIAA Fluid Dynamics Conference 4th AIAA Shear Flow Control Conference written by and published by . This book was released on 1997 with total page 354 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 1989 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instability and Transition in Unsteady Rotating Flows written by Sophie Alexandra Walter Calabretto and published by . This book was released on 2015 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unsteady flow of rotating fluids can exhibit some fascinating and elegant phenomena. The movement of fluid due to the rotation of an encompassing container, or the flow of fluid due to the rotation of a solid object immersed within a body of fluid, is of particular interest. Specifically, we focus on the dynamics resulting from an impulsive change in the rotation rate for both these internal and external flows, including the formation of boundary layers and their subsequent evolution, and the formation of instabilities. Using a combination of analytical, computational and experimental methods, we consider the flow induced by both a torus and a sphere, contained in an otherwise quiescent body of fluid, suddenly imparted with angular momentum. Our results agree well with previous work on this classical problem, known to exhibit a boundary-layer collision process, and we are able to take this problem further to consider the post-collision dynamics, encountering some new and exciting results, such as the development and propagation of a toroidal vortex pair, as a result of the boundary-layer collision, and instability of the radial jet. We also consider the flow within fluid-filled annular and toroidal containers, when there is a sudden change in the rotation rate of the container. Using both analytical and computational approaches, we explore the initial development of the impulsively generated axisymmetric boundary layer, its subsequent instability, and the larger scale transient features within this class of flows. This allows us to compare with and, perhaps, proffer an explanation for previously unexplained experimental results for the flow within a fluid-filled torus. In particular, we demonstrate that small imperfections in the torus surface, introduced during manufacture, can generate substantial secondary motion, considerably different from that which would arise if caused by centrifugal instabilities. This serves to highlight the often overlooked impact of small disturbances on the global dynamics of such flows.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1972 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Stability and Transition of Boundary Layer Flow written by Jafar MADADNIA and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1981 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Mathematical Reviews written by and published by . This book was released on 1987 with total page 1198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Peterson s Guide to Graduate Programs in Engineering and Applied Sciences written by and published by . This book was released on 1986 with total page 1110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Transition Over a Disk in Rotating Flows written by Joseph D. Cusimano and published by . This book was released on 1991 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
