Brief Communication: Dimensionality Reduction in Total Dynamic Mode Decomposition Using A Simple Geometric Method

Dynamic mode decomposition (DMD) and its variants have emerged as popular methods for the post-processing of fluid dynamics’ simulations in order to visualize dominant coherent structures and to reduce the practical degrees of freedom to a restricted set of ``modes’'. In this brief communication we provide a geometric method for choosing the number of modes for the Total DMD technique and test its efficacy using a synthetic example (to examine the effect of noise) and a cylinder wake case.