Owl-Inspired Ultra-Quiet Blade Designs

The nocturnal owl is known to have an unusually silent flight. The owl plumage has three unique features that are considered responsible for this acoustic stealth. We are numerically and experimentally investigating the silent flight of the night owl, and developing ways to adapt its unique feather features to enable ultra-quiet aircraft propulsion devices including UAVs. The specific research objectives are to

1. identify the true sources of sound produced in the process of turbulence-airfoil interaction,
2. investigate the unique feather adaptations (hush kit) of the owl that enable its silent flight; quantify their noise benefit and aerodynamic performance penalty, and
3. adapt the owl hush kit to develop ultra-quiet UAVs and jet engines. We have developed and verified a computational framework that can predict aerodynamically generated noise with high accuracy. This framework is now being used to develop and verify novel owl-inspired blade designs.

In the news

• 2017: ASME, Newswise, Iowa State News Service, Business Record, Design Engineering, Tech Xplore, Aerospace Technology, 3D Printing Industry, 3ders.org, Aerospace Manufacturing and Design,
• 2016: ISU College of Engineering, ISGC Comet, Ames Tribune

On the radio

• 2017: Iowa Public Radio, Radio Iowa, KBIA, KCUR, NET

Publications

Journal

1. Bodling, A., & Sharma, A. (2019). Numerical investigation of noise reduction mechanisms in a bio-inspired airfoil. Journal of Sound and Vibration, 453, 314–327.
   DOI BIB

   @article{bodling2019numerical,
     title = {Numerical investigation of noise reduction mechanisms in a bio-inspired airfoil},
     author = {Bodling, Andrew and Sharma, Anupam},
     journal = {Journal of Sound and Vibration},
     volume = {453},
     pages = {314--327},
     year = {2019},
     doi = {10.1016/j.jsv.2019.02.004},
     note = {SilentOwl},
     publisher = {Elsevier}
   }
   

2. Bodling, A., & Sharma, A. (2018). Numerical investigation of low-noise airfoils inspired by the down coat of owls. Bioinspiration & Biomimetics, 14(1), 016013.
   DOI BIB

   @article{bodling2018numerical,
     title = {Numerical investigation of low-noise airfoils inspired by the down coat of owls},
     author = {Bodling, Andrew and Sharma, Anupam},
     journal = {Bioinspiration \& biomimetics},
     volume = {14},
     number = {1},
     pages = {016013},
     year = {2018},
     doi = {10.1088/1748-3190/aaf19c},
     note = {SilentOwl},
     publisher = {IOP Publishing}
   }
   

3. Agrawal, B. R., & Sharma, A. (2016). Numerical analysis of aerodynamic noise mitigation via leading edge serrations for a rod–airfoil configuration. International Journal of Aeroacoustics, 15(8), 734–756.
   DOI BIB

   @article{agrawal2016numerical,
     title = {Numerical analysis of aerodynamic noise mitigation via leading edge serrations for a rod--airfoil configuration},
     author = {Agrawal, Bharat Raj and Sharma, Anupam},
     journal = {International Journal of Aeroacoustics},
     volume = {15},
     number = {8},
     pages = {734--756},
     year = {2016},
     doi = {10.1177/1475472X16672322},
     note = {SilentOwl},
     publisher = {SAGE Publications Sage UK: London, England}
   }
   

Conference proceedings

1. Bodling, A., & Sharma, A. (2018). Numerical Investigation of Low-Noise Airfoils Inspired by the Down Coat of Owls. 2018 AIAA/CEAS Aeroacoustics Conference.
   DOI BIB

   @inproceedings{bodling2018numericam,
     title = {Numerical Investigation of Low-Noise Airfoils Inspired by the Down Coat of Owls},
     author = {Bodling, Andrew and Sharma, Anupam},
     booktitle = {2018 AIAA/CEAS Aeroacoustics Conference},
     year = {2018},
     doi = {10.2514/6.2018-3925},
     note = {SilentOwl}
   }
   

2. Bodling, A. L., & Sharma, A. (2018). Implementation of the Ffowcs Williams-Hawkings equation: predicting the far field noise from airfoils while using boundary layer tripping mechanisms. Fluids Engineering Division Summer Meeting, V001T08A006.
   DOI BIB

   @inproceedings{bodling2018implementation,
     title = {Implementation of the Ffowcs Williams-Hawkings equation: predicting the far field noise from airfoils while using boundary layer tripping mechanisms},
     author = {Bodling, Andrew L and Sharma, Anupam},
     booktitle = {Fluids Engineering Division Summer Meeting},
     pages = {V001T08A006},
     year = {2018},
     organization = {American Society of Mechanical Engineers},
     note = {SilentOwl},
     doi = {10.1115/FEDSM2018-83385}
   }
   

3. Bodling, A., & Sharma, A. (2017). Noise reduction mechanisms due to bio-inspired airfoil designs. 17th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery.
   DOI BIB

   @inproceedings{bodling2017noise,
     title = {Noise reduction mechanisms due to bio-inspired airfoil designs},
     author = {Bodling, Andrew and Sharma, Anupam},
     booktitle = {17th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery},
     year = {2017},
     address = {Maui, HI, USA},
     note = {SilentOwl},
     doi = {10.2514/6.2017-0458}
   }
   

4. Bodling, A., Agrawal, B. R., Sharma, A., Clark, I., Alexander, W. N., & Devenport, W. J. (2017). Numerical investigations of bio-inspired blade designs to reduce broadband noise in aircraft engines and wind turbines. 55th AIAA Aerospace Sciences Meeting.
   DOI BIB

   @inproceedings{bodling2017numerical,
     title = {Numerical investigations of bio-inspired blade designs to reduce broadband noise in aircraft engines and wind turbines},
     author = {Bodling, Andrew and Agrawal, Bharat R and Sharma, Anupam and Clark, Ian and Alexander, William N and Devenport, William J},
     booktitle = {55th AIAA Aerospace Sciences Meeting},
     year = {2017},
     note = {SilentOwl},
     doi = {10.2514/6.2017-0458}
   }
   

5. Bodling, A., Agrawal, B. R., Sharma, A., Clark, I., Alexander, W. N., & Devenport, W. (2017). Numerical Investigations of Bio-Inspired Blade Designs to Reduce Broadband Noise in Aircraft Engines and Wind Turbines. 55th AIAA Aerospace Sciences Meeting.
   DOI BIB

   @inproceedings{bodlingSciTech2017,
     title = {Numerical Investigations of Bio-Inspired Blade Designs to Reduce Broadband Noise in Aircraft Engines and Wind Turbines},
     author = {Bodling, A. and Agrawal, B. R. and Sharma, A. and Clark, I. and Alexander, W. N. and Devenport, W.},
     booktitle = {55th AIAA Aerospace Sciences Meeting},
     address = {Grapevine, TX, USA},
     year = {2017},
     note = {SilentOwl},
     doi = {10.2514/6.2017-0458}
   }
   

6. Agrawal, B. R., & Sharma, A. (2016). Numerical investigations of bio-inspired blade designs to reduce broadband noise in aircraft engines and wind turbines. 54th AIAA Aerospace Sciences Meeting.
   DOI BIB

   @inproceedings{agrawal2016numericam,
     title = {Numerical investigations of bio-inspired blade designs to reduce broadband noise in aircraft engines and wind turbines},
     author = {Agrawal, Bharat R and Sharma, Anupam},
     booktitle = {54th AIAA aerospace sciences meeting},
     year = {2016},
     note = {SilentOwl},
     doi = {https://doi.org/0.2514/6.2016-0760}
   }
   

7. Agrawal, B., & Sharma, A. (2014). Aerodynamic Noise Prediction for a Rod-Airfoil Configuration using Large Eddy Simulations. 20th AIAA/CEAS Aeroacoustics Conference. http://arc.aiaa.org/doi/pdf/10.2514/6.2014-3295
   PDF DOI BIB

   @inproceedings{agrawal2014aerodynamic,
     title = {Aerodynamic Noise Prediction for a Rod-Airfoil Configuration using Large Eddy Simulations},
     author = {Agrawal, B and Sharma, A},
     booktitle = {20th AIAA/CEAS Aeroacoustics Conference},
     address = {Atlanta, Georgia, USA},
     year = {2014},
     doi = {10.2514/6.2014-3295},
     url = {http://arc.aiaa.org/doi/pdf/10.2514/6.2014-3295},
     note = {SilentOwl, Aeroacoustics},
     file = {Agrawal_AIAA_2014_Rod_Airfoil.pdf}
   }