Transverse Forces on Rough Cylinders in Harmonic Flow
Transverse Forces on Rough Cylinders in Harmonic Flow

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Published: 1977

Total Pages: 0

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The transverse forces acting on smooth and sand-roughened circular cylinders immersed in an harmonically oscillating flow have been measured using a recently constructed U-shaped water tunnel. The lift coefficients were found to depend on Keulegan-Carpenter number but independent of the Reynolds number within the range of relative roughness and Reynolds numbers tested. The results have shown that the lift coefficients for smooth cylinders at low Reynolds numbers are nearly identical with those obtained for rough cylinders at very high Reynolds numbers at the corresponding amplitude ratios.

Transverse Forces on Smooth and Rough Cylinders in Harmonic Flow at High Reynolds Numbers
Transverse Forces on Smooth and Rough Cylinders in Harmonic Flow at High Reynolds Numbers

Author: Neil Jon Collins

Publisher:

Published: 1976

Total Pages: 106

ISBN-13:

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The transverse forces acting on smooth and sand-roughened circular cylinders immersed in an harmonically oscillating flow have been measured using a recently constructed U-shaped water tunnel. The lift coefficient and the frequency of the alternating force have been determined. For smooth cylinders, the lift coefficients were found to depend on both the Reynolds and the Keulegan-Carpenter numbers for Reynolds numbers between about 20,000 and 150,000. For rough cylinders, the lift coefficients were found to be independent of the Reynolds number within the range of relative roughnesses and Reynolds numbers tested. The results have also shown that the lift coefficients for smooth cylinders at low Reynolds numbers are nearly identical with those obtained for rough cylinders at very high Reynolds numbers at the corresponding amplitude ratios. For both rough and smooth cylinders, the transverse force is a significant fraction of the in-line force and must be taken into consideration in the design of structures. It is recommended that the experiments be extended to the self-excited hydro-elastic oscillations of cylinders in harmonic flows. (Author).

Transverse Forces on Rough Cylinders in Harmonic Flow
Transverse Forces on Rough Cylinders in Harmonic Flow

Author: Peter John Henning

Publisher:

Published: 1977

Total Pages: 53

ISBN-13:

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The transverse forces acting on smooth and sand-roughened circular cylinders immersed in an harmonically oscillating flow have been measured using a recently constructed U-shaped water tunnel. The lift coefficients were found to depend on Keulegan-Carpenter number but independent of the Reynolds number within the range of relative roughness and Reynolds numbers tested. The results have shown that the lift coefficients for smooth cylinders at low Reynolds numbers are nearly identical with those obtained for rough cylinders at very high Reynolds numbers at the corresponding amplitude ratios.

Transverse Oscillations of Smooth and Rough Cylinders in Harmonic Flow
Transverse Oscillations of Smooth and Rough Cylinders in Harmonic Flow

Author: Suleyman Ozkaynak

Publisher:

Published: 1979

Total Pages: 0

ISBN-13:

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The dynamic response of elastically-mounted cylinders in a sinusoidally oscillating two-dimensional flow has been investigated both theoretically and experimentally. The experiments were carried out in a large U-shaped water tunnel, with smooth and sand-roughened circular cylinders. The results have been expressed in terms of lift coefficients, relative amplitudes of oscillation, Keulegan-Carpenter number, Reynolds number, Strouhal number, and a mass parameter. A theoretical analysis has been carried out by assuming the transverse force varies harmonically. Furthermore, the instantaneous values of the displacement have been predicted through the use of the Duhamel's integral. The results have shown that elastically-mounted cylinders undergo synchronous oscillations at a reduced velocity of 5.7 when the vortex shedding frequency coincides with the natural frequency of the cylinder. Away from the region of synchronization the cylinder is subjected to forced response by vortices shedding at a frequency smaller or larger than the natural frequency of the cylinder. (Author).

Vortex Shedding and Resistance in Harmonic Flow about Smooth and Rough Circular Cylinders at High Reynolds Numbers
Vortex Shedding and Resistance in Harmonic Flow about Smooth and Rough Circular Cylinders at High Reynolds Numbers

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Published: 1976

Total Pages: 0

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This report presents the results on an extensive experimental investigation of the in-line and transverse forces acting on smooth and rough circular cylinders placed in oscillatory water flow at Reynolds numbers up to 700,000, Keulegan-Carpenter numbers up to 150, and relative roughnesses from 0.002 to 0.02. The drag and inertia coefficients have been determined through the use of the Fourier analysis and the least-squares method. The transverse force (lift) has been analyzed in terms of its maximum, semi-peak-to-peak, and root-mean-square values. In addition, the frequency of vortex shedding and the Strouhal number have been determined.

In-line and Transverse Forces on Smooth and Rough Cylinders in Oscillatory Flow at High Reynolds Numbers
In-line and Transverse Forces on Smooth and Rough Cylinders in Oscillatory Flow at High Reynolds Numbers

Author: Turgut Sarpkaya

Publisher:

Published: 1986

Total Pages: 0

ISBN-13:

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"This report presents the results of an extensive experimental investigation of the in-line and transverse forces acting on smooth, sand-roughened, and marine-roughened circular cylinders (k/D=1/50) of identical length-to-diameter ratio (L/D=2) placed in a sinusoidally oscillating flow. The drag, inertia, and the maximum force coefficients have been determined through the use of the Fourier analysis. The transverse force (lift) has been analysed in terms of its root-mean-square value. In addition, the amplitude of the first ten harmonics have been determined. The results are presented in both graphical and tabulated form in terms of the Reynolds number, Keulegan-Carpenter number, relative roughness and the frequency parameter."--Abstract.

Vortex Shedding and Resistance in Harmonic Flow about Smooth and Rough Circular Cylinders at High Reynolds Numbers
Vortex Shedding and Resistance in Harmonic Flow about Smooth and Rough Circular Cylinders at High Reynolds Numbers

Author: Turgut Sarpkaya

Publisher:

Published: 1976

Total Pages: 194

ISBN-13:

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This report presents the results on an extensive experimental investigation of the in-line and transverse forces acting on smooth and rough circular cylinders placed in oscillatory water flow at Reynolds numbers up to 700,000, Keulegan-Carpenter numbers up to 150, and relative roughnesses from 0.002 to 0.02. The drag and inertia coefficients have been determined through the use of the Fourier analysis and the least-squares method. The transverse force (lift) has been analyzed in terms of its maximum, semi-peak-to-peak, and root-mean-square values. In addition, the frequency of vortex shedding and the Strouhal number have been determined.

In-Line and Transverse Forces on Smooth and Rough Cylinders in Oscillatory Flow at High Reynolds Numbers
In-Line and Transverse Forces on Smooth and Rough Cylinders in Oscillatory Flow at High Reynolds Numbers

Author: Turgut Sarpkaya

Publisher: Forgotten Books

Published: 2017-11-19

Total Pages: 182

ISBN-13: 9780260614261

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Excerpt from In-Line and Transverse Forces on Smooth and Rough Cylinders in Oscillatory Flow at High Reynolds Numbers: 4 July 1986, Interim Report for Period July 1985-July 1986 3. The drag, inertia, and the maximum force coefficients for smooth cylinders are at best a very weak function of the Reynolds number (re) for Re larger than about. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Scientific and Technical Aerospace Reports
Scientific and Technical Aerospace Reports

Author:

Publisher:

Published: 1987

Total Pages: 1126

ISBN-13:

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Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.