Meander dynamics: A nonlinear model without curvature restrictions for flow in open?channel bends

Despite the rapid evolution of computational power, simulation of meander dynamics by means of reduced and computationally less expensive models remains practically relevant for investigation of large?scale and long?term processes, probabilistic predictions, or rapid assessments. Existing meander models are invariantly based on the assumptions...

Saturation of curvature-induced secondary flow, energy losses, and turbulence in sharp open-channel bends: Laboratory experiments, analysis, and modeling

The paper investigates the influence of relative bend curvature on secondary flow, energy losses, and turbulence in sharp open-channel bends. These processes are important in natural streams with respect to sediment transport, the bathymetry and planimetry, mixing and spreading of pollutants, heat, oxygen, nutrients and biological species, and...

Modelling of planimetric/historical changes of the Geul river (The Netherlands)

This report presents the analyses and conclusions of a study on the planform evolution of the Geul river in the last 80 years. The results are compared with those of studies carried out by the Vrije Universiteit Amsterdam (VUA). The Geul river is to tributary of the Meuse River (The Netherlands). It has been straightened and protected against...

Processes and controls of meander development in the Allier, France

Morphological development was researched along five meanders in the Allier river, France. This includes large scale development of meander form and direction and guiding factors and processes. On a smaller scale channel processes that form morphology, including bars and (secondary) channels. Five meanders in the Allier river, France,...

Recent erosion and sedimentation processes in the Geul river

The Geul river in the southern part of the Netherlands has had a long history of channel straightening and bank protection, but during the past few decades, large stretches of the Geul have been allowed to meander freely. During fieldwork in June 2003, erosion and sedimentation processes, as well as channelisation measures, were mapped and...

The optimal meander planform shape from minimization of entropy production

AU over the world natui'al lowland rivers and streams are winding tlii'ough the sediments deposited in earlier times. These meandering rivers and streams show remarkable geometric similaiity: the ratio of the meander length to the width of the channel is constant. The process of meandering is thus independent of scale. Many theories and models...

Entropy and river meander planform

This study departs from the hypothesis that the often striifing geometric similarity and regularity of meanders is the result of the second law of thermodynamics applied to open dissipative systems. It is argued that along a meandering river the continuous production of entropy is as low and as uniform as possible. An expression of entropy...

A Nonlinear River Meandering Model and its Incorporation in a Landscape Evolution Model

A topographic steering river meandering (TSRM) model based on continuity of a simplified flow field through bends is developed. The equilibrium coupling between helical flow and sediment transport, as in Ikeda [1989] determines downstream variation of transverse bed slope. The model tests the hypothesis that meander development patterns can be...

Geomorphic and vegetative recovery processes along modified stream channels of West Tennessee

Hundreds of miles of streams in West Tennessee have been channelized or otherwise modified since the tum of century. After all or parts of a stream are straightened, dredged, or cleared, systematic hydrologic, geomorphic, and ecologic processes collectively begin to reduce energy conditions towards the premodified state. One hundred and .five...

Theory of river meanders

A mathematical model is developed for the calculation of flow field and bed topography in curved channels with an erodible bed. A small perturbation approach is used to linearize the governing equations. The downstream convective acceleration of the secondary flow is shown to give rise to a phase lag between secondary flow and channel centerline...

Computer simulated migration of meandering rivers in Minnesota

In the present work, a computer model for simulation of the migration of meandering rivers, developed by Beck [1985a], was applied to four rivers in the State of Minnesota. The computer model is based on a theoretical approach developed by Ikeda, Parker, and Sawai [1981]. The major objective was to evaluate the overall performance of the...

Numeriek model voor de ontwikkeling van vrije meanders in de Tana-rivier

Vrij meanderende rivieren veroorzaken grote problemen voor de aangrenzende gebieden, vanwege de vaak onvoorspelbare en onverwachte veranderingen in de oeverlijnen in betrekkelijk korte tijd. Een van die rivieren is de Tana-rivier in Kenia, waarvan de benedenloop door z'n sterk meanderende. karakter een bedreiging vormt voor diverse in cultuur...

Influence of secondary flow on meandring of rivers

A linear stability analysis of the governing equations for the bed and flow topography in straight alluvial channels is treated. The flow is described by a horizontal two-dimensional model, but secondary flow due to curvature of the streamlines is included. Further more knowledge about secondary flow inertia achieved in recent years is...

Meandering of small streams in Alluvium

Investigations were made at the Hydraulics Research Station of channels which achieved a meander pattern in alluvium through natural processes at discharges between 0.2 and 3.2 cusecs. These followed an earlier programme in which the behaviour of straight channels was studied. Discharge, sediment load, hydraulic gradient and channel geometry...