Category Archives: Acoustics

Aeroacoustic and Aerodynamic Interaction Effects Between eVTOL Rotors

My student presented his MS thesis on the aerodynamics and aeroacoustics of rotors. Abstract: Electric vertical take-off and landing (eVTOL) aircraft are characterized by their unconventional wing and electric rotor configurations, which involve both side-by-side and tandem rotor configurations. These configurations create unique aerodynamic and aeroacoustic flow-fields. We numerically investigate the interaction effects between rotor …

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A simplified semi-empirical model for long-range low-frequency noise propagation in the turbulent atmosphere

My student, Dr. Tianshu Zhang, and myself recently published a modified long range acoustic propagation model that handles turbulence in the atmosphere. The abstract is We present a semi-empirical long-range low-frequency acoustic propagation model, which accounts for atmospheric turbulence. Ostashev and Wilson’s scattering model is combined with a ray-theory based refraction model to account for …

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Acoustical Society of America – December 2022

This year my research group had a good showing at the Acoustical Society of America, Dec. 2022. I was happy to give a 20 minute talk myself on jet and rocket coherence and loading. My student, Dr. Alex Carr, who is now a Research Aerospace Engineering at NASA reported on his sonic boom predictions. My …

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Numerical prediction of loudness metrics for N-waves and shaped sonic booms in kinematic turbulence

Abstract, “The effects of a kinematic field of velocity fluctuations on the loudness metrics of two waveforms are examined with a three-dimensional one-way propagation solver. The waveforms consist of an N-wave and a simulated low-boom from NASA’s X-59 QueSST aircraft. The kinematic turbulence is generated using a von Karman composite spectrum, which is dependent on …

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Experiments in a Large-Boundary Layer Wind Tunnel: Propagation of Noise through the Turbulent Boundary Layer

My Group recently published a paper on a multiyear experiment campaign. We used the National Science Foundation Boundary Layer Wind Tunnel and sent acoustic waves through the boundary layer. We examined how turbulent structures altered the waveforms. The purpose is to create a high quality database available to the community to understand acoustic-turbulent interactions. Zhang, …

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Sankar’s Helicopter Aerodynamics

I’m really impressed with Professor Sankar’s website on fundamentals of aerodynamics of helicopters. It is often said in the aerospace community that if you understand the aerodynamics of helicopters then you can understand anything. It is really challenging! He has also posted a number of interesting items on aeroacoustics of rotorcraft. I have learned a …

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