Modal analysis of EHD jets through the SVD-based POD technique

An EHD flow has complex characteristics with superimposed characteristic structures of various scales due to the coupling effect of the electric and flow fields. This paper provides a new research perspective on active control techniques of EHD flows by unraveling the large-scale dynamic structure of the dominant electroconvection from the manifold of the jet. The SVD-based POD technique in our work marks the first comprehensive investigation of modal analysis for EHD jets, aiming at extracting reduced-order modes that capture the main features and exploring the mechanisms that govern these jets through a deeper understanding of dynamic physics. The findings indicate that large-scale coherent structures that determine the EHD flows regularly emerge in the low-order modes, and fine-scale vortex structures typically appear in the high-order modes. In addition, the POD-based flow field recovery technique can effectively remove the spurious vectors from the PIV dataset by simply excluding the high-order modes from the expansion during reconstruction.