HAWT: Broadband Acoustic Model

Acoustic (Broadband) Investigation on a HAWT, ANSYS Fluent CFD Simulation Tutorial

Description

This project investigates the acoustic performance of a horizontal axis wind turbine (HAWT), examining the noise it generates at multiple points throughout its surrounding domain. The simulation runs in a transient state using ANSYS Fluent, with the turbine rotating at 72 rad/s about its horizontal axis while an incoming air stream approaches at 15 m/s. Several monitoring points positioned both upstream and downstream of the turbine were selected for detailed noise investigation.

The acoustic results from this project are directly comparable to the companion study, "Acoustic (FWH) Investigation on a HAWT, ANSYS Fluent CFD Simulation Tutorial", which solves the same underlying model using the Ffowcs Williams-Hawkings (FWH) method instead — giving learners a direct side-by-side comparison of two distinct aeroacoustics prediction approaches applied to identical turbine conditions. Setting up this Broadband approach requires creating monitor points through the Surface–Create–Point tab under the Domain menu, then defining corresponding plots in the Report Definitions tab so acoustic quantities can be tracked transiently at each time step.

The geometry was designed in Design Modeler and meshed in ANSYS Meshing using tetrahedral elements, totaling 2,696,011 elements.

Methodology

Acoustic behavior was modeled using the Broadband Noise Source model, while turbine rotation was captured using the Moving Reference Frame (MRF) method applied within the Cell Zone Conditions. Turbulence was resolved using the k-ω SST model.

Conclusion

The acoustic results extracted at each defined monitoring point throughout the domain include Acoustic Power Level (dB), Surface Acoustic Power Level (dB), Power Spectral Density, and Lilley's self-noise source, among other parameters. Results show Acoustic Power Level increasing significantly along the turbine's blade surface with distance from the hub, tracking the corresponding rise in local velocity magnitude toward the blade tip.

These results can be directly compared against the companion FWH-based study referenced above, since both solve the identical turbine model using different acoustic prediction methods. The full set of resulting contours, plots, pathlines, and FFT spectra are provided as accompanying figures, offering a comprehensive view of the turbine's acoustic signature across the surrounding domain.