Quantifying the effect of turbulence intensity on turbulence-interaction noise of an airfoil using scale-resolving simulations

Noise pollution from ships is known to negatively impact wildlife. It is the low-frequency broadband noise component that can travel over large distances and is mostly relevant for marine wildlife. In the absence of cavitation, such as for tidal turbines, naval surface vessels and submarines, the low-frequency noise component is dominated by the interaction of the body with a turbulent inflow. The inflow turbulence generates pressure fluctuations on and near the surface of the body, thereby radiating sound to the far-field. This turbulence-interaction phenomenon is not fully understood yet.
The semi-analytical model by Amiet (1975) can be used to predict far-field turbulence-interaction noise for an airfoil, which predicts the far-field sound pressure level (S P L) as a function of the square of the turbulence intensity (T I). Amiet’s model, however, does not account for the geometrical properties of the airfoil. This work presents the results of a numerical study that aims to determine the effect of the turbulence intensity on the far-field turbulence-interaction noise for a NACA0008 airfoil. A comparison of the numerically predicted far-field noise to Amiet’s work is performed to evaluate the accuracy of Amiet for different receiver angles. The Ffowcs Williams and Hawkings (1969) (FW-H) acoustic analogy, which separates the generation and propagation of the sound, is adopted to estimate the S P L. Validation of the inflow turbulence and generated sound are performed by comparing one of the cases to a published experimental and numerical investigation for the same airfoil.