THE ANALYTICAL PROBLEM OF CONTROLLABLE PITCH PROPELLERS

A numerical method for the analysis of controllable pitch propeller characteristics is presented. This inverse problem is complicated due to the unknown circulation distribution and the off-design blade geometry. Therefore, a normal mode collocation method is introduced which simplifies the problem by a combination of design approaches. Starting with the transformation of blade geometry resulting from rotation about the spindle axis, a numerical lifting-surface computation is then applied on the exact three-dimensional basis and solved for the amplitude of each mode by collocation in order to obtain the circulation distribution and the thrust and torque thereof. The work has been modified by a reconstructed vortex lattice distribution and the consideration of hub image and deformed wake effect so that the accuracy is improved. This improvement can also be expected when the same effort is contributed on propeller blade design. Results are compared with a variety of propellers including the calculation of hydrodynamic spindle moment. Extensive studies can be made on blade surface pressure distribution and blade strength analysis as well as a quasi-static approach to the transient flow on a propeller operating in the wake behind a ship. Sample computer output and plots are included as illustrations.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  United States  02139
  • Authors:
    • Tsao, S S
  • Publication Date: 1975-5-5

Subject/Index Terms

Filing Info

  • Accession Number: 00099987
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: MS Thesis
  • Files: TRIS
  • Created Date: Oct 18 1975 12:00AM