Numerical and Experimental Investigation of a Trailing Edge Noise Generated by NACA 0012 Airfoil at Low Reynolds Numbers

Abstract Understanding the physical mechanisms of aerodynamic noise generation remains a key challenge in the development of low-noise airfoils for energy and aerospace applications. This study presents an extended numerical and experimental investigation of tonal trailing-edge noise generated by a NACA 0012 airfoil operating at low Reynolds numbers. Direct acoustic simulations based on a pressure-based compressible solver with a Large Eddy Simulation (LES) turbulence model are employed to resolve the unsteady flow field and acoustic response for selected reference conditions. In addition to numerical modeling, an extensive experimental campaign is conducted in anechoic facilities over a wide range of free-stream velocities from 7.5 to 24 m/s at zero angle of attack. The acoustic response is analyzed using Fast Fourier Transformation (FFT)-based spectral methods, allowing identification of primary and secondary tonal components and their evolution with flow velocity. A comparison between numerical and experimental results shows good agreement in the predicted tonal frequencies, exhibiting two-dimensional (2D) simulation is capable to predict the acoustic spectrum in general. While the sound pressure levels obtained from 2D simulations exceed experimental values by approximately 15–25 dB. This discrepancy is attributed to the inherent limitations of two-dimensional modeling and the absence of three-dimensional turbulence effects. The combined numerical–experimental approach provides valuable insight into the physical mechanisms governing tonal noise generation and establishes experimental scaling trends that can be used for future model validation and aerodynamic noise mitigation studies.