Numerical Investigation of Open Fan’s Tonal Noise Prediction in Low and High Speed Condition
Masakazu Sugiyama, Nassim Jaouani, Fabrice Falissard, Gabriel Reboul, Xavier Gloerfelt
Abstract
This paper highlights the link between the unsteady aerodynamics and Open Fan tonal noise generation prediction using the hybrid computational methodology combining the unsteady Reynolds Averaged Navier-Stokes (uRANS) simulation with Ffowcs-Williams and Hawkings (FWH) acoustic analogy. Among the various causes of noise, interaction noise emerges as a major noise source. Thus, an accurate evaluation of the interaction noise is consequently indispensable to correctly estimate the overall acoustic properties of an Open Fan. Careful attention must be paid to the computation of the aerodynamic flowfield to ensure that noise sources resulting from aerodynamic interactions are well captured, and their propagation up to the FWH coupling surface is accurate. Different acoustic prediction results are obtained between the FWH formulations (surface impermeable and permeable) as well as between the considered numerical schemes. This study emphasizes the sensitivities of numerical set-up for Open Fan noise prediction.