Aeroacoustics Projects

We have worked on several engine aeroacoustics problems. A few of them are described here.

Multipe pure tones (Buzzsaw) noise

Buzzsaw noise is generated in an aircraft engine when the front fan tip speed becomes supersonic. The rotor alone pressure field then can propagate through the nacelle and radiate out at blade passing harmonics. Due to manufacturing and installation tolerances, blade-to-blade variations lead to sound radiation at not just blade passing harmonics but at sub-harmonics of blade passing tone. These are called “buzzsaw” tones as they resemble the sound of a circular buzzsaw. We have developed methods to numerically predict buzzsaw noise through the use of RANS based CFD and simplified noise propagation and radiation models.

Rotor-OGV interaction tone noise

Aerodynamic interaction between adjacent bladerows of a turbomachine produces tonal and broadband noise. The interaction may be due to vorticity waves convecting and scattering as acoustic waves from the downstream stator, or due to the potential field of one bladerow impacting another. In a turbofan (aircraft) engine, it is primarily the viscous wake from the fan impacting the outlet guide vanes (OGVs) that produces fan noise. Tonal noise is caused by the mean velocity deficit in the wakes periodically hitting the OGV, and broadband noise by the turbulence impinging on the OGV. We have investigated both tonal and broadband noise due to this mechanism using advanced numerical and semi-analytical methods.

Pictures

Publications

Journal

  1. Ju, H., Mani, R., Vysohlid, M., & Sharma, A. (2015). Investigation of Fan Wake-OGV Interaction Broadband Noise. AIAA Journal, 53(12). https://arc.aiaa.org/doi/10.2514/1.J053167
  2. Han, F., Sharma, A., Paliath, U., & Shieh, C. (2014). Multiple pure tone noise prediction. Journal of Sound and Vibration, 333(25), 6942–6959.
  3. Sharma, A., & Chen, H. (2013). Prediction of aerodynamic tonal noise from open rotors. Journal of Sound and Vibration, 332(16), 3832–3845.
  4. Sharma, A., Chen, H., & Shieh, C. M. (2010). Linearized Navier-Stokes Analysis for Rotor-Stator Interaction Tone Noise Prediction. 16th AIAA Aeroacoustics Conference, AIAA 2010-3744. http://arc.aiaa.org/doi/abs/10.2514/6.2010-3744
  5. Sharma, A., Richards, S. K., Wood, T. H., & Shieh, C. M. (2009). Numerical prediction of exhaust fan-tone noise from high-bypass aircraft engines. AIAA Journal, 47(12), 2866–2879. http://arc.aiaa.org/doi/abs/10.2514/1.42208

Conference proceedings

  1. Li, A., Zeng, Z., & Sharma, A. (2022). Aeroacoustic analysis of an air amplifier. AIAA Scitech Forum, 2561.
  2. 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
  3. Agrawal, B. R., Rosenberg, A., & Sharma, A. (2014). Towards Identifying Contribution of Wake Turbulence to Inflow Noise from Wind Turbines. 2nd Symposium on OpenFOAM in Wind Energy.
  4. Sharma, A. (2013). Large Eddy Simulations for Predicting Aerodynamic Noise due to Rod Wake-Airfoil Interaction. RUZGEM, Middle Eastern Technical University.
  5. Ju, H., Mani, R., Vysohlid, M., & Sharma, A. (2013). Investigation of Fan Wake-OGV Interaction Broadband Noise. AIAA Aeroacoustics Meeting. http://arc.aiaa.org/doi/abs/10.2514/6.2013-2151
  6. Sharma, A., & Chen, H. (2012). Prediction of Tonal Aerodynamic Noise from Open Rotors. 18th AIAA/CEAS Aeroacoustics Conference, AIAA-2012. http://arc.aiaa.org/doi/pdf/10.2514/6.2012-2265
  7. Paliath, U., Han, F., Shieh, C. M., & Sharma, A. (2010). Multiple Pure Tone Noise Prediction for Acoustically Treated Aircraft Engines. 16th AIAA Aeroacoustics Conference, AIAA 2010-3714. http://arc.aiaa.org/doi/abs/10.2514/6.2010-3714
  8. Sharma, A., Richards, S. K., Wood, T. H., & Shieh, C. M. (2007). Numerical prediction of exhaust fan-tone noise from high-bypass aircraft engines. 13th AIAA/CEAS Aeroacoustics Conference, AIAA 2007-3700. http://arc.aiaa.org/doi/abs/10.2514/6.2007-3700
  9. Han, F., Shieh, C. M., Sharma, A., & Paliath, U. (2007). Multiple pure tone noise prediction and comparison with static engine test measurements. 13th AIAA/CEAS Aeroacoustics Conference, AIAA 2007-3523. http://arc.aiaa.org/doi/pdf/10.2514/6.2007-3523