气候变化领域集成服务门户(CCPortal): Drivers for mass and momentum exchange between the main channel and river bank lateral cavities

CCPortal

DOI	10.1016/j.advwatres.2020.103511
	Drivers for mass and momentum exchange between the main channel and river bank lateral cavities
	Ouro P.; Juez C.; Franca M.
发表日期	2020
ISSN	0309-1708
卷号	137
英文摘要	Large-Eddy Simulations (LES) are used to investigate the governing processes involved in mass and momentum transfer between the flow in the main channel and symmetrically-distributed lateral bank cavities. In-cavity free-surface velocities, based on laboratory measurements made in an open channel, are used to validate the numerical results. A main vortical structure dominates the in-cavity flow which, despite the shallow nature of the flow, features a remarked three dimensional dynamics. LES results outline the largest velocities through the mouth of the cavity are attained in two thin regions near the bottom-bed and free-surface. In the shear layers established between the main channel and cavities is where the main transfer of turbulent momentum is made between these two flow regions, and the numerical simulations capture well the instantaneous coherent flow structures, e.g. Kelvin-Helmholtz vortices. LES captures a low-frequency standing wave phenomenon even with a rigid-lid approximation adopted at the free-surface boundary. Momentum exchange between cavities and main channel is analysed using the Reynolds Averaged momentum equation in the transverse direction, revealing that the pressure gradient term is the unique contributor to flushing momentum out of the cavities whilst convection and Reynolds normal stress terms are responsible for its entraining into the cavity. Furthermore, sediment deposition areas documented in the laboratory experiments are linked with the simulated hydrodynamics, which correlate with regions of low turbulent kinetic energy and vertical velocities near the bottom of the channel. Overall, the results shed new light into the complex mechanisms involved in mass and momentum transfer; this will aid to design embayments more efficiently regarding sediment transport processes. © 2020 Elsevier Ltd
关键词	Banks (bodies of water)Hydrodynamics Kinetic energy Kinetics Large eddy simulation Mass transfer Momentum Momentum transfer Sediment transport Shear flow Turbulence Free-surface boundaries Kelvin-helmholtz vortices Laboratory measurements Mass and momentum transfers River bank Sediment transport process Three-dimensional dynamics Turbulent kinetic energy Open channel flow cavitation deposition large eddy simulation mass transport momentum transfer open channel flow river bank turbulence vortex
语种	英语
来源机构	Advances in Water Resources
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/131850
推荐引用方式 GB/T 7714	Ouro P.,Juez C.,Franca M.. Drivers for mass and momentum exchange between the main channel and river bank lateral cavities[J]. Advances in Water Resources,2020,137.
APA	Ouro P.,Juez C.,&Franca M..(2020).Drivers for mass and momentum exchange between the main channel and river bank lateral cavities.,137.
MLA	Ouro P.,et al."Drivers for mass and momentum exchange between the main channel and river bank lateral cavities".137(2020).