12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
In the present study turbulence characteristics from Reynolds Averaged Navier-Stokes simulations are used as input for the analytical prediction of fan broadband noise due to the interaction of the fan rotor wake turbulence with the outlet guide vanes. The aerodynamic excitation is modeled with a von K´arm´an spectrum and the blade response with the Sears function extended with a term considering the non-compactness of the source. The influence of different turbulence models, from state-of-the-art two-equation models to a Reynoldsstress transport model, on the simulated turbulence characteristics and consequently on the broadband noise prediction is investigated. Furthermore the impact of the two-equation model extensions for the effects of rotation, transition and the stagnation point is analyzed and discussed. The predicted noise spectra are compared to the experimental test data of the NASA Source Diagnostic Test fan rig. It has been found that different turbulence models and extensions can lead to a variation of predicted broadband interaction noise of up to 2dB.