Item Details

Development and Application of a Method for Predicting Rotor Free Wake Positions and Resulting Rotor Blade Air Loads: Volume 1 Model and Results

by S. Gene Sadler
Format
Book; Government Document; Online; EBook
Published
Washington, D.C. : National Aeronautics and Space Administration ; Springfield, Va. : For sale by the National Technical Information Service [distributor], 1971.
Language
English
Series
NASA Contractor Report
Summary
Rotor wake geometries are predicted by a process similar to the startup of a rotor in a free stream. An array of discrete trailing and shed vortices is generated with vortex strengths corresponding to stepwise radial and azimuthal blade circulations. The array of shed and trailing vortices is limited to an arbitrary number of azimuthal steps behind each blade. The remainder of the wake model of each blade is an arbitrary number of trailing vortices. Vortex element end points were allowed to be transported by the resultant velocity of the free stream and vortex-induced velocities. Wake geometry, wake flow, and wake-induced velocity influence coefficients are generated by this program for use in the blade loads portion of the calculations. Blade loads computations include the effects of nonuniform inflow due to a free wake, nonlinear airfoil characteristics, and response of flexible blades to the applied loads. Computed wake flows and blade loads are compared with experimentally measured data. Predicted blade loads, response and shears and moments are obtained for a model rotor system having two independent rotors. The effects of advance ratio, vertical separation of rotors, different blade radius ratios, and different azimuthal spacing of the blades of one rotor with respect to the other are investigated.
Description
121 p. : ill. ; 27 cm.
Mode of access: Internet.
Notes
  • "NASA CR-1911."
  • "December 1971."
  • Cover title.
  • Includes bibliographical references (p. 69-70).
Series Statement
NASA contractor report ; NASA CR-1911
Other Forms
Also available online from the NASA Technical Reports Server (http://ntrs.nasa.gov/). Address as of 04/05/06: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720007340%5f1972007340.pdf.
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Technical Details

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    a| Development and application of a method for predicting rotor free wake positions and resulting rotor blade air loads. n| Volume 1, p| Model and results / c| by S. Gene Sadler.
    260
      
      
    a| Washington, D.C. : b| National Aeronautics and Space Administration ; a| Springfield, Va. : b| For sale by the National Technical Information Service [distributor], c| 1971.
    300
      
      
    a| 121 p. : b| ill. ; c| 27 cm.
    490
      
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    a| NASA contractor report ; v| NASA CR-1911
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    a| "NASA CR-1911."
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    a| "December 1971."
    500
      
      
    a| Cover title.
    504
      
      
    a| Includes bibliographical references (p. 69-70).
    520
      
      
    a| Rotor wake geometries are predicted by a process similar to the startup of a rotor in a free stream. An array of discrete trailing and shed vortices is generated with vortex strengths corresponding to stepwise radial and azimuthal blade circulations. The array of shed and trailing vortices is limited to an arbitrary number of azimuthal steps behind each blade. The remainder of the wake model of each blade is an arbitrary number of trailing vortices. Vortex element end points were allowed to be transported by the resultant velocity of the free stream and vortex-induced velocities. Wake geometry, wake flow, and wake-induced velocity influence coefficients are generated by this program for use in the blade loads portion of the calculations. Blade loads computations include the effects of nonuniform inflow due to a free wake, nonlinear airfoil characteristics, and response of flexible blades to the applied loads. Computed wake flows and blade loads are compared with experimentally measured data. Predicted blade loads, response and shears and moments are obtained for a model rotor system having two independent rotors. The effects of advance ratio, vertical separation of rotors, different blade radius ratios, and different azimuthal spacing of the blades of one rotor with respect to the other are investigated.
    530
      
      
    a| Also available online from the NASA Technical Reports Server (http://ntrs.nasa.gov/). Address as of 04/05/06: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720007340%5f1972007340.pdf.
    536
      
      
    a| Preformed by Rochester Applied Science Associates, Inc., Rochester, N.Y., for Langley Research Center under b| NAS1-8448
    538
      
      
    a| Mode of access: Internet.
    650
      
    7
    a| Numerical analysis. 2| nasat
    650
      
    7
    a| Flow velocity. 2| nasat
    650
      
    7
    a| Flow geometry. 2| nasat
    650
      
    7
    a| Aerodynamic loads. 2| nasat
    650
      
    7
    a| Vortices. 2| nasat
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    7
    a| Unsteady flow. 2| nasat
    650
      
    7
    a| Turbulent wakes. 2| nasat
    650
      
    7
    a| Rotor blades (turbomachinery) 2| nasat
    650
      
    0
    a| Numerical analysis.
    650
      
    0
    a| Aerodynamic load.
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    0
    a| Unsteady flow (Aerodynamics)
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    a| Wakes (Aerodynamics)
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    a| Turbomachines x| Blades.
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    a| Rotors.
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    a| Langley Research Center.
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    a| Rochester Applied Sciences Associates.
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    b| UIU c| UIUC d| 20141113 s| google u| uiug.30112106856922 y| 1971 r| pd q| bib

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