Computationally efficient source grid selection and source interpolation in computational aeroacoustics applied to an axial fan

The noise generation of an axial fan is mainly caused by flow-induced sound. For this fan case, a hybrid approach separating flow and acoustics is suitable due to its low Mach number flow. Such a computationally efficient hybrid workflow requires a robust conservative mesh-to-mesh transformation of the acoustic sources as well as a proper mesh refinement to guarantee good convergence behavior. In doing so, we focus on the mesh-to-mesh data interpolation. Two interpolation algorithms of different complexity are compared and applied to the aeroacoustic computation of an axial fan. The basic cell-centroid approach is generally suited for fine computational acoustic (CA) meshes, while the more complex cut-volume method yields better results for coarse acoustic meshes. Although the cell-centroid interpolation scheme produces source artifacts inside the propagation domain, a grid study using the grid convergence index shows monotonic convergence behavior for both interpolation methods.