Acoustic characterization and its relation to POD and SPOD of flow around tandem cylinders

Flows around two tandem cylinders are simulated using an immersed-boundary method. Cases in the lock-in, transitional and quasi-periodic regimes are investigated. The flowfield is used to provide sources to analyze acoustic pressure at the far field. Both proper orthogonal decomposition (POD) and spectral POD (SPOD) methods are performed for the flowfield to extract flow physics. The relations between the acoustic characterization and the flowfield POD and SPOD are then discussed.