VIBRATIONS OF A MARINE PROPELLER OPERATING IN A NONUNIFORM INFLOW. RESEARCH AND DEVELOPMENT REPORT

The effect of blade vibration on the unsteady forces developed by an elastic marine propeller is investigated for a controlled laboratory situation. The study involves the development of a theory for a flexible propeller operating in a spatially nonuniform inflow velocity field and a series of experimental tests. Measurements of unsteady propeller forces in a 24-inch water tunnel are presented for two model propellers whose fundamental resonance frequencies are excited by a nonuniform inflow field. Measured unsteady thrust and torque, presented as a function of excitation frequency, show distinctly different elastic effects--one propeller demonstrates a large force amplification near its resonance frequency while the other did not. The simple theoretical model explains the difference as being due to the differing amounts of induced hydrodynamic damping; there is a large hydrodynamic damping in one case and a small amount in the other case. Another result of the study is that blade vibration can significantly reduce the unsteady forces transmitted to the propeller shaft over a certain range of excitation frequencies. Calculated forces are in general agreement with the experimental measurements. (Author)

  • Corporate Authors:

    David Taylor Naval Ship R&D Center

    Bethesda, MD  United States  20084
  • Authors:
    • BROOKS, J E
  • Publication Date: 1980-4

Media Info

  • Pagination: 140 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00326091
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: DTNSRDC-80/056
  • Files: TRIS
  • Created Date: Nov 19 1981 12:00AM