USE OF TWO - DIMENSIONAL UNSTEADY FLOW THEORY WITH LOW ASPECT - RATIO BLADES

It is known that if two-dimensional airfoil theory is used to calculate the mean forces on a marine propeller blade, the answer obtained is likely to over-estimate the true answer by a factor of typically three. It is shown that when unsteady forces (at shaft-rate or blade-rate) are being calculated, the use of unsteady two-dimensional airfoil theory is much more acceptable, for being associated with errors of about 60% for shaft-rate forces and 25% for blade-rate forces. It is pointed out that the more accurate unsteady lifting-surface theory is prohibitively expensive for use regularly as a design tool, and further, that the accuracy of the answer may be limited in any case by the accuracy of the measured wake data. (Author)

• Corporate Authors:

  Admiralty Research Laboratory

  Teddington,   England 
• Authors:
  • Murray, M T
• Publication Date: 1973-5

Media Info

• Pagination: 13 p.

Subject/Index Terms

• TRT Terms: Aerodynamic lift; Blade loading; Propellers; Vehicle design
• Old TRIS Terms: Lifting surface theory; Propeller design; Propeller theory; Unsteady loading
• Subject Areas: Design; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00053916
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: ARL/M/N17
• Files: TRIS
• Created Date: May 7 1974 12:00AM