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Lumley, J.L. (author), Khajeh-Nouri, B. (author)
A rational closure technique is presented for the first and second moment-equations in a stratified, contaminated turbulent flow, Following the application of high Reynolds/Peclet number approximations, remaining third moments are expanded about the isotropic, homogeneous state. The stratified, uncontaminated case reduces to seventeen equations...
report 1973
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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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Justesen, P. (author)
Close to the bottom the no-slip condition will retard the flow and cause a boundary layer to develop. In nature this boundary layer will for most practical purposes be turbulent and the bed will be rough. Usually the boundary layer is confined to a thin layer close to the bed having a typical thickness of 0.2 m under surface gravity waves. The...
report 1985
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Kranenburg, C. (author)
A k-model is formulated that consists of the turbulent kinetic energy equation and an algebraic expression for the mixing length taking into account the influence of stratification. Applicability of the model is restricted to shallow, nearly horizontal flows. For local-equilibrium flows the model reduces to the well-known mixing-length...
report 1985
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Chen, C.J. (author), Singh, K. (author)
The use of second order closure turbulence model in predicting turbulent flows is known to be more successful than the classical mixing length model. However, it is found that if the turbulence constants are not altered or modified, the second order closure turbulence model is unable to predict satisfactorily f or some flows such as round jet...
report 1985
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Uittenbogaard, R.E. (author)
report 1986
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Flokstra, C. (author)
report 1986
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Hoffmans, G.J.C.M. (author)
The general purpose of this research project is to model mathematically the scour-hole downstream of a structure (2-D). The model has to simulate the development of the scour as a function of time. Basically two models are necessary namely a flow model and a morphological model. The latter has to describe the bed- and suspended load and the...
report 1988
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Lehfeldt, R. (author)
The density distribution within a fluid is of great importance for flow and transport phenomena in geophysical computational fluid dynamics. All turbulent exchange processes are influenced by buoyancy effects and must be adequately considered in numerical models. Parameterizations of the vertical eddy viscosity and eddy diffusivity are presented...
report 1991
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Bernard, R.S. (author), Schneider, M.L. (author)
Without some correction for the interaction between lateral curvature and vertically nonuniform velocity, depth-averaged numerical models cannot predict the gradual migration of high velocity toward the outside of channel bends. Conventional depth-averaging does not account for the curvature-induced secondary flow that gives rise to the...
report 1992
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Uittenbogaard, R.E. (author)
report 1993
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Rodi, W. (author), Bonnin, J.C. (author), Buchal, T. (author)
This document contains the calculation results for 5 test cases and the description of calculation methods submitted to the ERCOFTAC Workshop on Data Bases and Testing of Calculation Methods for Turbulent Flows held in Karlsruhe from April 3 to 7, 1995. The workshop was an outcome and marked the end of the research project "Data Validation and...
report 1995
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Kester, J.A.T.M. van (author), Uittenbogaard, R.E. (author), Dingemans, M.W. (author)
report 1996
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Verwey, A. (author), Agtersloot, R.C. (author)
report 1998
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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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Panara, D. (author), Porta, M. (author), Schoenfeld, T. (author)
The use of wall functions has been investigated for LES and URANS numerical simulation in pulsating and oscillating channel flow applications. The results show that the wall function approach is accurate in the so-called quasi-steady regime but there are discrepancies with the experimental results in the intermediate frequency range. A special...
conference paper 2006
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Meyers, J. (author), Sagaut, P. (author)
A theoretical analysis is presented on the dependence of the standard and variational multi-scale Smagorinsky models on the proximity of the LES filter width Delta to the integral length scale of turbulence L on the one hand, and to the Kolmogorov scale eta on the other hand. Moreover modifications of the models are formulated, which respond...
conference paper 2006
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Geurts, B.J. (author)
We analyze the evolution of a diffusion flame in a turbulent mixing layer using large-eddy simulation. The large-eddy simulation includes Leray regularization of the convective transport and approximate inverse filtering to represent the chemical source terms. The Leray model is compared to the more conventional dynamic mixed model. The location...
conference paper 2006
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Bijlard, M.J. (author)
doctoral thesis 2009
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Bierbooms, W.A.A.M. (author)
doctoral thesis 2009
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