Author(s): Bing-Qing Deng; Zixuan Yang; Lian Shen
Linked Author(s):
Keywords: Open channel flows; Free surface; Turbulence; Wave-turbulence interaction
Abstract: Research on turbulent motions in shallow open waters is essential for environmental protection, aquaculture, and river hydraulic engineering. In these environments, the kinematic and dynamic boundary conditions at the free surface can significantly constrain and distort turbulent flows. Recent numerical and laboratory studies of open channel flows have revealed that the influence of the free surface extends beyond the near-surface source layer, penetrating into the bulk flow region, where very large-scale motions (VLSMs) play a critical role in contributing to turbulent kinetic energy and Reynolds shear stresses. Understanding how free surfaces impact VLSMs in open channel flows is crucial for providing a theoretical basis for developing turbulence models in various applications. Given that the linear lifting-up effect is one of the key mechanisms in the sustaining cycle of VLSMs, we utilize linear non-modal analysis to investigate the effects of a deformable free surface on VLSMs in plane open channel flows.
Year: 2025