Wind turbine sound propagation: Comparison of a linearized Euler equations model with parabolic equation methods

TL;DR

This paper compares a linearized Euler equations model with the parabolic equation method for predicting wind turbine sound propagation, highlighting their similarities and differences in two different terrain scenarios.

Contribution

It introduces the use of linearized Euler equations for sound propagation prediction and compares its performance with the established parabolic equation method.

Findings

Both methods produce similar noise predictions in flat terrain.

Differences observed in complex terrain scenarios.

Linearized Euler equations provide time-domain solutions.

Abstract

Noise generated by wind turbines is significantly impacted by its propagation in the atmosphere. Hence, for annoyance issues an accurate prediction of sound propagation is critical to determine noise levels around wind turbines. This study presents a method to predict wind turbine sound propagation based on linearized Euler equations. We compare this approach to the parabolic equation method, which is widely used since it captures the influence of atmospheric refraction, ground reflection, and sound scattering at a low computational cost. Using the linearized Euler equations is more computationally demanding but can reproduce more physical effects as fewer assumptions are made. An additional benefit of the linearized Euler equations is that they provide a time-domain solution. To compare both approaches, we simulate sound propagation in two distinct scenarios. In the first scenario, a wind turbine is situated on flat terrain; in the second, a turbine is situated on a hilltop. The results show that both methods provide similar noise predictions in the two scenarios. We find that while some differences in the propagation results are observed in the second case, the final predictions for a broadband extended source are similar between the two methods.