In-line and transverse forces on smooth and sand-roughened cylinders in oscillatory flow at high Reynolds numbers
Authors
Sarpkaya, Turgut
Subjects
Oscillating Flow
Wave Forces
Drag and Inertia Coefficients
Roughened Cylinders
Harmonic Flow
Fluid Loading on Ocean Structures
Wave Forces
Drag and Inertia Coefficients
Roughened Cylinders
Harmonic Flow
Fluid Loading on Ocean Structures
Advisors
Date of Issue
1976-06-04
Date
4 June 1976
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
This report presents the results of an extensive experimental investigation of the in-line and transverse forces acting on smooth and sand- roughened circular cylinders placed in oscillatory flow at Reynolds numbers up to 1,500,000, Keulegan-Carpenter numbers up to 100, and relative sand- roughnesses form 1/800 to 1/50. 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 analysed 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. The results have shown that (a) for smooth cylinders, all of the coefficients cited above are functions of the Reynolds and Keulegan-Carpenter numbers, particularly for Reynolds numbers larger than about 20,000; (b) for rough cylinders, the force coefficients also depend on the relative roughness k/D and differ significantly from those corresponding to the smooth cylinder; and that (c) the use of the 'frequency parameter' D sq/nu T and the roughness Reynolds number U sub m k/nu allow a new interpretation of the present as well as the previously obtained data.
Type
Technical Report
Description
Series/Report No
Department
Mechanical and Aerospace Engineering (MAE)
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
NPS-69SL76062
Sponsors
National Science Foundation
Funder
Grant No.AG-477
Format
72 p.
Citation
Sarpkaya, Turgut. In-line and transverse forces on smooth and sand-roughened cylinders in oscillatory flow at high Reynolds numbers. No. NPS-69SL76062. NAVAL POSTGRADUATE SCHOOL MONTEREY CA, 1976.
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.