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

Abstract

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.