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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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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 Vliet, E. (author) doctoral thesis 2003
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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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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
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Li, Y. (author), McLaughlin, J.B. (author), Kontomaris, K. (author), Portela, L. (author)This paper presents results for the behavior of particle-laden gases in a small Reynolds number vertical channel down flow. Results will be presented for the effects of particle feedback on the gas-phase turbulence and for the concentration profile of the particles. The effects of density ratio, mass loading, and particle inertia will be...journal article 2001
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Tsinober, A. (author), Vedula, P. (author), Yeung, P.K. (author)The properties of acceleration fluctuations in isotropic turbulence are studied in direct numerical simulations (DNS) by decomposing the acceleration as the sum of local and convective contributions (aL = ?u/?t and aC = u??u), or alternatively as the sum of irrotational and solenoidal contributions [aI = ??(p/?) and aS = ??2u]. The main emphasis...journal article 2001
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Kranenburg, C. (author)The Prandtl mixing-length model of turbulent exchange of mass and momentum is applied to calculate the entrainment of overlying water into a layer of suspended fine sediment at a horizontal bed. In the field the flow and turbulence in such a concentrated benthic suspension (CBS) are driven by a streamwise pressure gradient resulting from the...report 1999
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Westin, K.J.A. (author), Henkes, R.A.W.M. (author)Boundary layer transition induced by high levels of free stream turbulence (FSl), so called bypass transition, can not be predicted with conventional stability calculations (e.g. the en-method). The use of turbulence models for transition prediction has shown some success for this type of flows, and the present study is a further investigation...book 1998
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Henkes, R.A.W.M. (author)An overview is given on the background of different turbulence models that can be used to compute boundary layers in external aerodynamics, such as for aircraft. The overview includes algebraic models (Cebeci-Smith, Baldwin-Lomax), a half-equation model (Johnson-King), two-equation models ( K-E-K-), and a differential Reynolds-stress model. The...book 1998
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Suastika, I.K. (author)In this report we present some results of a laboratory pilot study which has been conducted to test a method to artificially enhance the turbulence of a water flow in a laboratory flume. The purpose of this test is to provide data which will be used to verify whether the method is suitable for the study of the dissipative effects of turbulence...report 1998
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- Hanjalic, K. (author), Peeters, T.W.J. (author) book 1997
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- Van Gool, P.C.A. (author) doctoral thesis 1997
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Bijvelds, M.D.J.P. (author)In this report the water flow in harbours, that are situated on a river, are considered. Due to the flow velocity difference between the river and the harbour, a turbulent mixing layer develops at the harbour entrance. The shallowness of the water induces the coexistance of two disparate turbulent length scales in these regions. Besides the ...report 1997
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- Den Toonder, J.M.J. (author) doctoral thesis 1996