Aeroacoustic Investigation of a Generic Rotor Model Using a Hybrid Finite-Volume, Finite-Element Computational Scheme with Sliding Mesh Interfaces

Computing the flow induced sound in rotating systems such as in ventilators and compressors yields additional challenges compared to setups without moving parts. In our contribution we apply a newly developed, hybrid computational scheme to a two-dimensional geometry, consisting of two infinitely long cylinders rotating around a common axis in a quiescent medium. The dominant sound producing phenomenon in this setup is the vortex shedding at the individual cylinders as well as the interaction between them. The flow is computed by solving the incompressible NavierStokes (NS) equations using the open source software OpenFOAM, which provides the Arbitrary Mesh Interface (AMI) to handle rotating systems. Due to an energy conserving interpolation scheme, it is possible to use a much coarser computational grid for the acoustic calculation to increase computational efficiency. The propagating sound is computed by solving the acoustic wave equation by the Finite-Element (FE) solver CFS++, which uses a Nitsche type mortaring to couple rotating and stationary mesh. To account for the free radiation condition at the domain boundary, the perfectly matched layer (PML) technique is applied.