Turbulence statistics and very-large-scale motions in decelerating open-channel flow

作者：Peng Zhang, Yanchong Duan, Danxun Li, Jiang Hu, Wenjie Li, Shengfa Yang · 发表于：Physics of Fluids · 年份：2019 · DOI：10.1063/1.5129111 · 被引用次数：23 · 研究领域：Fluid Dynamics and Turbulent Flows、Hydrology and Sediment Transport Processes、Aerodynamics and Acoustics in Jet Flows

This study experimentally examined the turbulent characteristics of decelerating open-channel flow based on particle imaging velocimetry measurement. The decelerating flow shows a similar velocity profile to that in uniform flow, but it exhibits greater turbulence intensity and Reynolds stress. Statistical evidence of the presence of very-large-scale motions (VLSMs) in decelerating open-channel flows was presented for the first time. The results indicate that VLSMs in decelerating flows can survive further away from the wall when compared to other wall-turbulence flows. The contribution rate of the VLSMs to the turbulent kinetic energy and the Reynolds stress in the decelerating open-channel flow is slightly lower than that in channels, boundary layers, and pipe flows.