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- Labrujere, T.E. (author), Schipholt, G.J. (author), de Vries, O. (author) report 1972
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de Vries, O. (author)Research on high-lift devices has been carried out at NLR along the following lines. An experimental approach consisting of pressure measurements at the mid-span section of a twodimensional wing (chord about 0.6 m, span 2 m), with boundary layer control at the tunnel wallwing junctions by blowing slots. Premature flow separation can be avoided...report 1972
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de Vries, O. (author)The deformation of the vortex sheet "behind a 30 sweptback wing (span 1.5 m, chord 0.3 m) has heen measured in the LST 3x2. Three types of measurements have been applied: - a total head survey (viscous wake) - yaw measurements (sidewash variation across vortex sheet) - vortex indicator measurements (vortex wake). Only a part (60%) of the total...report 1973
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- de Vries, O. (author) report 1973
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Labrujère, T.E. (author), de Vries, O. (author)The defomation of a vortex sheet behind a 30 degrees swept back wing, has been measured in a low-speed wind tunnel. The measurements included: - A total-head survey behind the wing, - Sidewash measurements across the wake, - Measurements of trailing vorticity by a vortex indicator. It has been found, that 60 percent of the trailing vorticity is...report 1974
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Labrujère, T.E. (author), de Vries, O. (author)The present report considers the validity of the representation of the wake by discrete trailing vortices as is common practice in potential theoretical calcualtions. Theoretical results, obtained with a method developed at NLR, are compared with experimental results obtained at NLR for a 30° swept back wing. The shape of the vortex sheet as...report 1974
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de Vries, O. (author)De energieopwekking door verschillende typen windgedreven rotoren, is aan de hand van eenvoudige TDeschcuwingen nagegaan. Het voornaamste doel was, zich te oriënteren omtrent de mogelijkheid voor het NLR om op aërodynamisch gebied "bijdragen te leveren tot de verdere ontwikkeling van deze rotoren. Verder kwam de vraag naar voren rotoren met...report 1974
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- de Vries, O. (author), Schipholt, G.J.L. (author) report 1975
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de Vries, M. (author)Processes on degradation and aggradation of rivers have a speed depending on the characteristics of the rivers. Starting from the basic equations a morphological timescale, characterising these processes, is defined. This morphological time-scale is estimated for various rivers.report 1975
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Plantema, G. (author), van Herk, J. (author), Veerling, C. (author), Horvat, A. (author), de Vries, S.B. (author)Ontwikkeling van prefab-viaducten en –tunnels, projectorganisatie en –beheersing, lay-out bij nieuwe overstapstations, de metro/sneltram van Coolhaven naar Ommoord-west, het architectonisch ontwerp, geotechnische aspecten, constructieve aspecten van enkele bijzondere kunstwerken.report 1977
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de Vries, O. (author)This report deals with the contribution of NLR to the first phase of the National Research Program on Wind Energy, which consisted mainly of theoretical studies. A so-called rigid rotor computer program vjas compiled for a Darrieus wind turbine, to predict the aerodyna.mic performance of the turbine and the blade loading due to aerodynamic and...report 1977
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de Vries, O. (author)This report describes the theory for the calculation of the performance and the blade loading of a Darrieus wind turbine, rotating in a steady wind (rigid rotor program). A discussion of calculated results has been given. The results of the calculations, obtained with the performance theory, depend strongly on the profile data used. A future...report 1977
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- de Vries, Maarten H. (author) master thesis 1978
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de Vries, O. (author)Some blade element theories for the calculation of the aerodynamic performstnce of a horizontal-axis wind turbine have been surveyed. With one of these theories, a parameter study has been carried out. A Cp-optimized rotor design leads to a non-linearly tapered and highly twisted rotor blade. It seems possible to simplify the blade geometry with...report 1978
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- de Vries, Maarten H. (author) master thesis 1979
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de Vries, O. (author)A two-bladed horizontal-axis wind turbine, with a diameter of 0.75 m and a solidity ratio of 0.0674, has been tested in the LST 3 x 2 of NLR. Most of the tests have been carried out at an almost constant Reynolds number of about 3.5 X 10/5. Comparison with a simple performance prediction method showed an acceptable agreement in qualitative...report 1979
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- de Vries, R.J. (author) report 1980
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- de Vries, P.F. (author) report 1980
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- de Vries, P.F. (author) report 1981
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de Vries, O. (author), den Blanken, M.H.G. (author)A second series of tests has been performed on a two-bladed horizontal axis wind turbine in the lowspeed wind timnel LST 3x2 of NLR. The tests have been carried out at a Reynolds number of 3.5x10 , referred to the blade chord. The investigation included the effect of turbulence on the turbine performance, the determination of the wake blockage...report 1981