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Blanckaert, K. (author), De Vriend, H.J. (author)In spite of its importance, little is known about the turbulence characteristics in open-channel bends. This paper reports on an experimental investigation of turbulence in one cross section of an open-channel bend. Typical flow features are a bicellular pattern of cross-stream circulation (secondary flow) and a turbulence activity in the outer...journal article 2005
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Breugem, W.P. (author)The study of flows over permeable walls is relevant to many applications. Examples are flows over and through porous river beds, vegetation, snow, heat exchangers of foam metal, and oil wells. The main objectives of this thesis are to gain insight in the influence of wall permeability on both laminar and turbulent flows, and to develop a...doctoral thesis 2005
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Breugem, W.P. (author), Boersma, B.J. (author)A direct numerical simulation (DNS) has been performed of turbulent channel flow over a three-dimensional Cartesian grid of 30×20×9 cubes in, respectively, the streamwise, spanwise, and wall-normal direction. The grid of cubes mimics a permeable wall with a porosity of 0.875. The flow field is resolved with 600×400×400 mesh points. To enforce...journal article 2005
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- Mudde, R.F. (author) journal article 2005
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Groen, J.S. (author)In this project a detailed experimental analysis was performed of the dynamic flow field in bubbly flows, with the purpose of determining local hydrodynamics and scale effects. Measurements were done in gas-liquid systems (air-water bubble columns) and in gas-solid systems (air-sand bubbing fluidized beds) of different size. Amongst others with...doctoral thesis 2004
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de Ruijter, R. (author)Downstream of man-made hydraulic structures, bed protections made of granular material are often used to prevent erosion of the bottom. The stones in the top layer of such granular filters must be able to withstand the hydraulic forces. Probably the best-known formula that is used to determine the stability of granular bed material is the design...master thesis 2004
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Doelman, N.J. (author), Hinnen, K.J.G. (author), Stoffelen, F.J.G. (author), Verhaegen, M.H. (author)An Adaptive Optics (AO) system for astronomy is analysed from a control point of view. The focus is put on the temporal error. The AO controller is identified as a feedback regulator system, operating in closed-loop with the aim of rejecting wavefront disturbances. Limitations on the performance of feedback regulator systems are discussed. The...conference paper 2004
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Hughes, T.J.R. (author), Wells, G.N. (author), Wray, A.A. (author)Energy transfers within large-eddy simulation (LES) and direct numerical simulation (DNS) grids are studied. The spectral eddy viscosity for conventional dynamic Smagorinsky and variational multiscale LES methods are compared with DNS results. Both models underestimate the DNS results for a very coarse LES, but the dynamic Smagorinsky model is...journal article 2004
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Kenjere, S. (author), Hanjali?, K. (author), Bal, D. (author)A magnetic field, imposed on turbulent flow of an electrically conductive fluid, is known to cause preferential damping of the velocity and its fluctuations in the direction of Lorentz force, thus leading to an increase in stress anisotropy. Based on direct numerical simulations (DNS), we have developed a model of magnetohydrodynamic (MHD)...journal article 2004
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Geers, L.F.G. (author)Because of their high efficiency and their ability to provide high heat transfer rates, impinging jets are applied for rapid cooling and heating in a wide variety of industrial processes. However, the physical phenomena controlling the heat transfer from impinging jets are to a large degree unknown. The goal of the present project was to gain a...doctoral thesis 2004
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Holmen, J. (author), Hughes, T.J.R. (author), Oberai, A.A. (author), Wells, G.N. (author)The variational multiscale method has been shown to perform well for large-eddy simulation (LES) of turbulent flows. The method relies upon a partition of the resolved velocity field into large- and small-scale components. The subgrid model then acts only on the small scales of motion, unlike conventional LES models which act on all scales of...journal article 2004
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Vrieling, A.J. (author)This thesis deals with mixing of passive scalars in a turbulent flow. The passive scalars are released in a turbulent plane channel flow and interpreted as either non-reactive components or reactive components that are involved in a competitive-consecutive reaction system. The evolution of these passive scalars under influence of turbulent...doctoral thesis 2003
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Van Staveren, W.H.J.J. (author)The response of aircraft to stochastic atmospheric turbulence plays an important role in aircraft-design (load calculations), Flight Control System (FCS) design and flight-simulation (handling qualities research and pilot training). In order to simulate these aircraft responses, an accurate mathematical model is required. Two classical models...doctoral thesis 2003
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- van Vliet, E. (author) doctoral thesis 2003
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- Jongeling, T.H.G. (author), Jagers, H.R.A. (author), Blom, A. (author) report 2003
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- Jongeling, T.H.G (author), Jagers, H.R.A. (author) report 2002
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Van Prooijen, B.C. (author), Uijttewaal, W.S.J. (author)The development of large coherent structures in a shallow mixing layer is analyzed. The results are validated with experimental data obtained from particle tracking velocimetry. The mean flow field is modeled using the self-similarity of the velocity profiles. The characteristic features of the down-stream development of a shallow mixing layer...journal article 2002
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- Hofland, B. (author) report 2002
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- Hanjalic, K. (author) journal article 2002
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Manceau, R. (author), Hanjali?, K. (author)A new approach to modeling the effects of a solid wall in one-point second-moment (Reynolds-stress) turbulence closures is presented. The model is based on the relaxation of an inhomogeneous (near-wall) formulation of the pressure–strain tensor towards the chosen conventional homogeneous (far-from-a-wall) form using the blending function ?, for...journal article 2001