Broadband noise prediction using large eddy simulation and a frequency domain method

A new LES-acoustic analogy method for accurate flow and broadband noise prediction is proposed. A frequency domain method for the generalized Lighthill acoustic analogy theory is derived in detail and the final equations for code is provided which can help to bridge the gap between the flow field prediction and the acoustic field prediction for those who are interested in acoustic results but lack of acoustic prediction ability. The hybrid method (LES and acoustic analogy method) for broadband noise prediction is validated using the rod-airfoil interaction problem. Both flow field results and acoustic field results are compared with experimental results and other numerical results in detail. The flow field results agree very well with the experimental results and other numerical results. The predicted acoustic results and experimental results also reach good agreement both in far field acoustic pressure Power Spectral Density (PSD) and noise directivity. The method developed in the paper proves to be an effective tool for broadband noise prediction. In addition, the different span correction methods for the acoustic pressure spectrum are also discussed.