Searched for: author:"De Vriend, H.J."
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De Vriend, H.J. (author)
Het probleem van de stroming in een rivierbocht is door ir. M.B. de Groot geabstraheerd tot het probleem van de stroming in een cilindrische bak met verticale as, afgesloten met een om die as draaiend, vlak deksel. Een nadeel van de bovengenoemde abstractie is, dat men overgaat op een fundamenteel ander aandrijvend mechanisme: de schuifspanning...
report 1971
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De Vriend, H.J. (author)
Dit literatuuroverzicht betreft publikaties over de stroming door een bocht in een open kanaal met vaste bodem en een constante, rechthoekige dwarsdoorsnede, waarbij men zich in het bijzonder bezig houdt met de verdeling van de snelheden en de ligging van de waterspiegel. Er is een onderscheid gemaakt tussen publikaties over experimenteel...
report 1972
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De Vriend, H.J. (author)
The axisymmetrical, viscous flow in curved channels is considered in the case where the hydraulic radius of the cross-section is small with respect to the average radius of curvature of the bend. First Ananyan's theory on this subject is reconsidered, using a regular perturbation method. The results are applied to a specific channel with a...
report 1972
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De Vriend, H.J. (author)
Uitgaande van de Reynoldsvergelijkingen met de bijbehorende randvoorwaarden wordt een vereenvoudigd wiskundig model afgeleid voor ondiepe bochtige rivieren. met als voornaamste uitgangspunten: - de vertikale afgeleiden van de snelheden zijn groot t.o.v. de horizontale - de schuifspanningseffekten overheersen de traagheids- (advectieve) effekten....
report 1976
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De Vriend, H.J. (author)
Dit rapport behandelt de numerieke' oplossing van de over de waterdiepte gemiddelde massa- en impulsiebalansvergelijkingen voor de permanente, turbulente stroming in een ondiepe, bochtige rivier, zoals die zijn afgeleid in "A mathematical model of steady flow in curved shallow channels" (ref. 1, zie pag. 4). Het eerste oogmerk hiervan is een...
report 1976
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De Vriend, H.J. (author)
As an intermediate step between earlier investigations on fully developed laminar flow in curved channels of shallow rectancular wet cross-section and the mathematical modeling of turbulent flow in river bends, a mathematical model of developing laminar flow in such channels is investigated. The most important assumptions made in addition to...
report 1978
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De Vriend, H.J. (author)
A mathematical model of steady, fully developed laminar flow in curved ducts is developed and used to derive a simplified computation method to be applied in another mathematical model predicting the flow in river bends. The laminar flow model is verified by comparing its results with analytical, numerical and experimental results reported in...
report 1978
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De Vriend, H.J. (author)
After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river bends. A mathematical model is developed for this...
report 1979
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De Vriend, H.J. (author)
The relationship between streamline curvature and bed resistance in shallow water flow with little side constraint, as derived in 1970 by H.J. Schoemaker, is reconsidered. Schoemaker concluded that the bed resistance causes the curvature of a free streamline to grow exponentially with the distance along this streamline, thus giving rise to a...
report 1979
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De Vriend, H.J. (author)
This report describes an extensive experiment on steady turbulent flow in a rather sharply curved U-shaped flume with a shallow rectangular cross-section, under almost the same conditions as earlier, less extensive measurements in the same flume. The experiment was carried out as a part of a research project aiming at a mathematical model of the...
report 1979
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Kalkwijk, J.P.T. (author), De Vriend, H.J. (author)
The mathematical model presented describes the flow in rivers of which: i the depth is small compared with the width, ii the width is small compared with the radius of curvature, iii the horizontal length scale of the bottom variations is of the order of magnitude of the width. Within these limits, the channel alignment can be arbitrary and it...
report 1980
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De Vriend, H.J. (author)
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...
doctoral thesis 1981
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De Vriend, H.J. (author), Geldof, H.J. (author)
Results of a mathematical model for the depth-averaged main flow velocity in shallow river bends are compared with measurements in two consecutive sharply-curved short bends in the river Dommel, The Netherlands. The computed main velocity distribution agrees rather well with the measured one in the larger part of each bend. Near the bend exits,...
report 1983
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Dingemans, M.W. (author), Stive, M.J.F. (author), Bosma, J. (author), De Vriend, H.J. (author), Vogel, J.A. (author)
conference paper 1986
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Stive, M.J.F. (author), De Vriend, H.J. (author)
conference paper 1987
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De Vriend, H.J. (author), Stive, M.J.F. (author)
journal article 1987
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De Vriend, H.J. (author), Reinalda, R. (author), Derks, H. (author)
The 1981 and 1982/1983 field measurement campaigns in the nearshore zone at Egmond, The Netherlands, are outlined and the access to the resulting data sets is indicated. Besides, the use of these data for mathematical model validation is discussed and some general remarks are made on the set-up of synoptic field campaigns to generate data sets...
report 1987
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De Vriend, H.J. (author), Koch, F.G. (author)
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...
report 1987
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De Vriend, H.J. (author), Roelvink, J.A. (author)
Het onderzoek van kustprocessen in het algemeen, alsmede de recente studie van de Nederlandse kust in het kader van de Nota Kustverdediging, hebben tal van nieuwe inzichten opgeleverd in de werking van de zandige Nederlandse kust als morfologisch systeem. In dit rapport worden de verkregen resultaten geintegreerd tot een samenhangend beeld van...
report 1989
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Stive, M.J.F. (author), Roelvink, D.A. (author), De Vriend, H.J. (author)
conference paper 1990
Searched for: author:"De Vriend, H.J."
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