Leveraging modal structure similarity for simulation of spatially evolving wakes

Abstract

We present a new methodology to enable efficient simulation of high Reynolds number wakes. In this approach, a body-exclusive hybrid simulation at Re = 5 x 10^4 is initialized using inflow fields reconstructed from a lower Reynolds number (Re = 5 x 10^3) body-inclusive simulation. Spectral Proper Orthogonal Decomposition (SPOD) is employed to identify dominant coherent structures, and a low-rank reconstruction generates physically meaningful inflow conditions. The resulting simulations accurately recover key large-scale flow, including the vortex shedding mode, and match the spectral content of a fully body-inclusive Re = 5 x 10^4 reference simulation beyond an adjustment region. SPOD eigenspectra confirm agreement across both low and high frequencies. This strategy achieves over an order-of-magnitude reduction in computational cost by avoiding direct high-Re body-inclusive simulations, offering a scalable framework for simulating complex wakes using low Re as well as reduced-order inflow prescriptions.