Comparative analysis of spatiotemporal coherent structures in a spouted fluidized bed using data-driven methods

Examining the spatiotemporal coherence structures constitutes a significant issue in investigating the hydrodynamics of spouted fluidized beds. This study employed data-driven methods of proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) to identify and analyze the coherent structures presented in a spouted fluidized bed. It was found that the POD modes have higher defined energy and richer structure than DMD modes. The mean modes of POD and DMD exhibit reflectional symmetry, similar to the time-averaged flow field from the computational fluid dynamics–discrete element method simulation. Under the same energy ratio criterion, fewer spatial modes are required for POD reconstruction than for DMD reconstruction. POD is more suitable for low-dimensional reconstruction of the instantaneous flow field for the spouted fluidized bed, while DMD excels at constructing the mean flow field and the detailed instantaneous flow field. This study provides valuable insights into the coherent structures and flow field reconstruction in spouted fluidized beds.