"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:21873027-98ea-42eb-afdb-e2fc48271ae3","http://resolver.tudelft.nl/uuid:21873027-98ea-42eb-afdb-e2fc48271ae3","Sediment transport in rivers - report on experimental and theoretical investigations","De Vriend, H.J.; Koch, F.G.","TU Delft","1987","I: Flow of water in a curved open channel with a fixed plane bed II: Flow of water in a curved open channel with a fixed uneven bed III: Accuracy of measurements in a curved open channel In this report the flow of water in a curved open channel, which consists of a38 m long straight section followed by a 90° bend with a radius of 50 m (see Figure 1), has been investigated. The channel cross-section was rectangular with a horizontal concrete bed, a width of 6 m, and a depth of flow of 0.25 m, and measurements were executed at two discharges: 0.610m3 /s and0.305 m3/s (average velocities of about 0.4 m/s and 0.2 m/s respectively). During these experiments the following phenomena were investigated: a. the vertical distribution of the horizontal velocity components (main flow and helical flow) ; b. the horizontal distribution of the total depth-averaged velocity; and c, the horizontal distribution of the water surface elevation. The experimental results have been compared with the results of a mathematical model of flow in curved open channels, developed at the Laboratory of Fluid Mechanics of the Delft University of Technology.The vertical distributions of the main velocity turned out to be highly similar throughout the flow field, the distribution being well described by the logarithmic profile. The helical velocities derived from the measured data were too inaccurate to compare them more than roughly with their theoretical distributions. The point in a cross-section where the observed depth-averaged velocity reaches its maximum lies near the inner wall in the first part of the curve and moving downstream it gradually shifts towards the outer wall. This phenomenon is attributed to the advective influence of the helical flow. As this influence is not accounted for in the present mathematical model, this model does not predict the phenomenon. The water surface configuration agreed reasonably well with the computed configuration.","sediment transport; river flow; river morphology; bed stability","en","report","Delft Hydraulics","","","","","","","","","","","","TOW",""
"uuid:d42e1810-6657-4941-9703-a2c08a6550f1","http://resolver.tudelft.nl/uuid:d42e1810-6657-4941-9703-a2c08a6550f1","Steady flow in shallow channel bends","De Vriend, H.J.","Kalkwijk, J.P.T. (promotor)","1981","Making use of a mathematical model solving the complete NavierStokes equations for steady flow in coiled rectangular pipes, fully-developed laminar flow in shallow curved channels is analysed physically and mathematically. Transverse convection of momentum by the secondary flow is shown to cause important deformations of the main velocity distribution. The model is also used to investigate simplified computation methods for shallow channels. The usual 'shallow water approximation' is shown to fail here, but a method starting from similarity hypotheses for the main and the secondary flow works well. On the basis of this method, a simplified mathematical model of steady turbulent flow in river bends is developed and verified using the results of laboratory experiments and fully three-dimensional flow computations. This model works well for shallow and mildly curved channels, but it shows important shortcomings if the channel is less shallow or sharplier curved.","River bend; river flow; river morphology","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""