The paper investigates the possibility of extracting energy from surrounding flow by a two-dimensional hydrofoil oscillating through a gravity wave in water, or by an airfoil in gusts. The greatest possible rate of energy extraction is obtained by the optimum mode of heaving and pitching of the hydrofoil, which is determined by the method of variational calculation of parameters. It is found that energy extration is impossible if the incident flow is uniform, and becomes feasible only when the primary flow contains a wave component having a transverse velocity distribution normal to both the mean free stream and the wing span. When such waves of sufficiently large amplitude are present, not only flow energy but also a net mechanical power can be extracted from the surrounding flow.

  • Supplemental Notes:
    • Also availabile in Journal of Ship Research, V14,N1 pp 66-78, March 1972. Revision of report dated 24 November 1971
  • Corporate Authors:

    California Institute of Technology

    Division of Engineering and Applied Science
    1200 East California Boulevard
    Pasadena, CA  United States  91125
  • Authors:
    • Wu, TYT
  • Publication Date: 1971-12-13

Media Info

  • Pagination: 14 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00035615
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: E97A.23
  • Contract Numbers: N00014-67-A-00940012, NSF-GK-10216
  • Files: TRIS
  • Created Date: Oct 27 1973 12:00AM