POD Study on Large-Scale Structures of Viscoelastic Turbulent Drag-Reducing Flow

Proper orthogonal decomposition (POD) analysis of three-dimensional large-scale structures for drag-reducing flow is performed. The input data needed by POD are provided by direct numerical simulation (DNS). The large-scale structures include main fluctuating structures of velocity and conformation tensor. These structures are all represented in three dimensions. Through the analyses, the characteristic structures of drag-reducing flow with different viscoelasticity are studied. The results show that larger viscoelasticity is related to larger conjunction of fluctuating conformation tensors and their stronger interactions with velocity fluctuations.