TRANSVERSE FORCES ON SMOOTH AND ROUGH CYLINDERS IN HARMONIC FLOW AT HIGH REYNOLDS NUMBERS

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 number 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-elastic oscillations of cylinders in harmonic flows. (Author)

• Corporate Authors:

  Naval Postgraduate School

  1 University Circle
  Monterey, CA  United States  93943
• Authors:
  • Collins, N J
• Publication Date: 1976-6

Media Info

• Pagination: 106 p.

Subject/Index Terms

• TRT Terms: Cylindrical bodies; Force; Lift drag ratio; Roughness; Waves
• Old TRIS Terms: Wave forces on structures
• Subject Areas: Design; Marine Transportation;

Filing Info

• Accession Number: 00142816
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: MS Thesis
• Files: TRIS
• Created Date: Dec 15 1976 12:00AM