Comparison of predicted fan broadband noise using a two- versus a three-dimensional synthetic turbulence method

Abstract

Fan broadband noise - in particular broadband rotor-stator-interaction noise - is a significant noise source of modern aircraft. However, its accurate prediction remains a challenge. RANS-informed synthetic turbulence methods are increasingly applied for these types of noise predictions as they present a compromise between accuracy and computational effort. Two-dimensional simulations are especially inexpensive but their results are not necessarily representative for the entire fan stage. To investigate this issue, the authors present the expansion of an approach based on the fast Random Particle Mesh method to three-dimensional space and apply it to the AneCom AeroTest Rotor 1 fan stage. The three-dimensional simulations are compared in detail to two-dimensional simulations to quantify and analyze observed differences between the results. As a consequence, a correction technique for the two-dimensional simulation results is proposed.