On the Stability of Flow in Rotating Pipes PDF Download
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Author: Hassan M. Nagib
Publisher:
ISBN:
Category :
Languages : en
Pages : 114
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Book Description
The stability of flow in rotating pipes is investigated experimentally. The results of the investigation also have a bearing on the stability of flow in the core of swirling flows in stationary ducts and free vortices. Solid body rotation is found to have a destabilizing effect when superposed on a pipe entrance region axial velocity profile. The range of swirl ratios up to four is investigated using two different approaches: dye streaks visualization and hot-thermistor anemometry. As the swirl ratio is increased from zero to four, the axial Reynolds number at which laminar flow breaks down decreases from 2500 to 900. These results agree in trend with the limit axial Reynolds number value of 82.9 that was recently obtained by analytical investigations of the stability of a viscous fully developed axial velocity profile subject to a rapid, almost rigid rotation in pipes. The present results also suggest that the destabilizing trend due to solid body rotation may also hold for other axial velocity profiles and indicates a possible new mechanism of confined flow instability that takes place at lower Reynolds numbers than previously believed possible.
Author: Hassan M. Nagib
Publisher:
ISBN:
Category :
Languages : en
Pages : 114
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Book Description
The stability of flow in rotating pipes is investigated experimentally. The results of the investigation also have a bearing on the stability of flow in the core of swirling flows in stationary ducts and free vortices. Solid body rotation is found to have a destabilizing effect when superposed on a pipe entrance region axial velocity profile. The range of swirl ratios up to four is investigated using two different approaches: dye streaks visualization and hot-thermistor anemometry. As the swirl ratio is increased from zero to four, the axial Reynolds number at which laminar flow breaks down decreases from 2500 to 900. These results agree in trend with the limit axial Reynolds number value of 82.9 that was recently obtained by analytical investigations of the stability of a viscous fully developed axial velocity profile subject to a rapid, almost rigid rotation in pipes. The present results also suggest that the destabilizing trend due to solid body rotation may also hold for other axial velocity profiles and indicates a possible new mechanism of confined flow instability that takes place at lower Reynolds numbers than previously believed possible.
Author: Jean-Pierre Demurger
Publisher:
ISBN:
Category :
Languages : en
Pages : 228
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Book Description
Author: Josette Strohl
Publisher:
ISBN:
Category :
Languages : en
Pages : 104
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Book Description
The hydrodynamic stability of an incompressible Poiseville flow in a rotating pipe is studied. The analysis considers linear, viscid non-axisymmetric disturbances. For the case of a very large rotation, the range of axial wave numbers at which unstable modes may exist is determined, and a critical Reynolds number (based on axial flow), 82,93 is found. The transition is stationary with respect to a co-ordinate system that rotates with the pipe, and it occurs at the fundamental mode of the tangential disturbance. In addition, Reynolds number as well as the axial and tangential wave numbers for some values of growth rate are determined and eigenfunctions for some of the cases considered are calculated. (Author).
Author: D. D. Joseph
Publisher: Springer Science & Business Media
ISBN: 364280991X
Category : Science
Languages : en
Pages : 295
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Book Description
The study of stability aims at understanding the abrupt changes which are observed in fluid motions as the external parameters are varied. It is a demanding study, far from full grown"whose most interesting conclusions are recent. I have written a detailed account of those parts of the recent theory which I regard as established. Acknowledgements I started writing this book in 1967 at the invitation of Clifford Truesdell. It was to be a short work on the energy theory of stability and if I had stuck to that I would have finished the writing many years ago. The theory of stability has developed so rapidly since 1967 that the book I might then have written would now have a much too limited scope. I am grateful to Truesdell, not so much for the invitation to spend endless hours of writing and erasing, but for the generous way he has supported my efforts and encouraged me to higher standards of good work. I have tried to follow Truesdell's advice to write this work in a clear and uncomplicated style. This is not easy advice for a former sociologist to follow; if I have failed it is not due to a lack of urging by him or trying by me. My research during the years 1969-1970 was supported in part by a grant from the Guggenheim foundation to study in London.
Author: United States. National Bureau of Standards
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 696
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Book Description
Author:
Publisher:
ISBN:
Category : Weights and measures
Languages : en
Pages : 540
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Book Description
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 232
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Book Description
Author: Stephen Jarvis
Publisher:
ISBN:
Category : Pipe
Languages : en
Pages : 116
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Book Description
The theory of hydrodynamic stability for infinitesimal disturbances is applied to the steady symmetric annular flow of two incompressible fluids in a vertical pipe. The resulting 12 x 12 complex determinant for the determination of curves of neutral stability is reduced, by suitable approximations, to an 8 x 8 one, and numerical methods are used to determine some ne * utral curves for air-water mixtures.(Author).
Author: United States. National Bureau of Standards
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 360
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Book Description
Author: Michael P. Paidoussis
Publisher: Academic Press
ISBN: 0123973139
Category : Science
Languages : en
Pages : 885
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Book Description
The first of two books concentrating on the dynamics of slender bodies within or containing axial flow, Fluid-Structure Interaction, Volume 1 covers the fundamentals and mechanisms giving rise to flow-induced vibration, with a particular focus on the challenges associated with pipes conveying fluid. This volume has been thoroughly updated to reference the latest developments in the field, with a continued emphasis on the understanding of dynamical behaviour and analytical methods needed to provide long-term solutions and validate the latest computational methods and codes. In this edition, Chapter 7 from Volume 2 has also been moved to Volume 1, meaning that Volume 1 now mainly treats the dynamics of systems subjected to internal flow, whereas in Volume 2 the axial flow is in most cases external to the flow or annular. Provides an in-depth review of an extensive range of fluid-structure interaction topics, with detailed real-world examples and thorough referencing throughout for additional detail Organized by structure and problem type, allowing you to dip into the sections that are relevant to the particular problem you are facing, with numerous appendices containing the equations relevant to specific problems Supports development of long-term solutions by focusing on the fundamentals and mechanisms needed to understand underlying causes and operating conditions under which apparent solutions might not prove effective
