Implementing the Ffowcs Williams and Hawkings acoustic analogy in ANTARES

The aerodynamic noise radiating from an unsteady flow can be extracted by an acoustic analogy approach from time-resolved Computational Fluid Dynamic (CFD) simulations. For this purpose, a Ffowcs Williams and Hawkings (FW-H) post-processor is developed, based on an advanced time formulation. The method is coded in Python and embedded in Antares, which is a CFD companion software developed by Cerfacs, France. The availability in Antares of input and output data interfaces for structured and unstructured CFD geometries and solutions provides a good software development platform. The new post-processor is tested on a hierarchy of noise sources of increasing complexity, for which comparison is made with existing data. The radiating field from a simple monopole is considered first, with progression to a subsonic jet test case, for which acoustic data have been estimated by Bogey and Bailly (2006). CFD results obtained at Cerfacs (France), using a compressible Large Eddy Simulation (LES) on the same test case, provide the input to the acoustic analogy to estimate the far-field noise. The far-field noise predictions are compared to the acoustic results obtained with the CFD software elsA (Onera, France), that uses the same Ffowcs Williams and Hawkings acoustic analogy formulation and these are found in good agreement.