On the space-time decomposition and reconstruction of the pump-jet propulsor flow field

In this numerical study, a modal approach based on the stress blend eddy simulation (SBES) was employed to investigated the morphology and development regime of the vortices in a pump-jet propulsor (PJP). Modal analysis was conducted on the corresponding surfaces to gain insights into the evaluation of the flow field, with a focus on spectral proper orthogonal decomposition (SPOD) and dynamic mode decomposition (DMD). These methods consider both temporal and spatial domain decomposition. By comparing the modes obtained from SOPD and DMD, it was observed that the coherent structure morphology exhibited similarities with only minor differences. The results indicated that the flow field could be effectively reconstructed using a few low-order modes. Both SPOD and DMD accurately captured the flow field, expect in the downstream hub region where chaotic flow was present. This study provides valuable insights into wake flow field of the PJP and sheds light on the understanding of vortex dynamics. •Temporally analyzed a pump-jet propulsor's flow field using spectral Proper Orthogonal Decomposition (SPOD) method.•A comparison was made between the flow field modes obtained by Dynamic Mode Decomposition (DMD) and spectral POD methods.•Both modal analysis methods can accurately and rapidly reconstruct the flow field, excepting a specific chaotic regime.