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Ferrari, S. (author), Badas, M.G. (author), Besalduch, L.A. (author), Querzoli, G. (author)
We present a novel algorithm, namely Feature Tracking Velocimetry (FTV), which is less sensitive to the appearance and disappearance of particles and to high velocity gradients than classical Particle Image Velocimetry (PIV). The basic idea of FTV is to compare windows only where the motion detection may be successful, that is where there are...
conference paper 2013
document
Hoan, N.T. (author), Booij, R. (author), Hofland, B. (author), Stive, M.J.F. (author), Verhagen, H.J. (author)
The current research is aimed at finding a proper relation between flow forces acting on the bed and the bed response. To this end, experiments were carried out in which both the bed response (quantified by a dimensionless entrainment rate) and the flow field (velocity and turbulence intensity distributions) are measured. The three available...
conference paper 2007
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Geurts, B.J. (author)
Non-uniform filtering of the Navier-Stokes equations expresses itself, next to the turbulent stresses, in additional closure terms known as commutator errors. These terms require explicit subgrid modeling if the non-uniformity of the filter is sufficiently pronounced. We derive expressions for the magnitude of the mean flux, the turbulent stress...
conference paper 2006
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De Borst, R. (author), Hulshoff, S.J. (author), Lenz, S. (author), Munts, E.A. (author), Van Brummelen, E.H. (author), Wall, W.A. (author)
The basic idea of multiscale methods, namely the decomposition of a problem into a coarse scale and a fine scale, has in an intuitive manner been used in engineering for many decades, if not for centuries. Also in computational science, large-scale problems have been solved, and local data, for instance displacements, forces or velocities, have...
conference paper 2006
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De Hoogh, J. (author), Kuerten, J.G.M. (author)
To investigate the behavior of the concentration of a passive scalar in a turbulent flow with realistic high Schmidt numbers, one needs a very fine grid to capture all length-scales that are present in the concentration. An efficient method to increase the spatial resolution without a drastic raise of the computational costs is to apply a Local...
conference paper 2006
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De Borst, R. (author), Hulshoff, S.J. (author), Lenz, S. (author), Munts, E.A. (author), Van Brummelen, E.H. (author), Wall, W.A. (author)
The basic idea of multiscale methods, namely the decomposition of a problem into a coarse scale and a fine scale, has in an intuitive manner been used in engineering for many decades, if not for centuries. Also in computational science, large-scale problems have been solved, and local data, for instance displacements, forces or velocities, have...
conference paper 2006
document
Hoan, N.T. (author), Booij, R. (author), Hofland, B. (author), Stive, M.J.F. (author), Verhagen, H.J. (author)
The current research is aimed at finding a dimensionless stability parameter for non-uniform flow in which the effect of turbulence is incorporated. To this end, experiments were carried out in which both the bed response (quantified by a dimensionless entrainment rate) and the flow field (velocity and turbulence intensity distributions) are...
conference paper 2007
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Cargnelutti, M. (author), Breugem, W.A. (author), Portela, L.M. (author), Mudde, R.F. (author), Uijttewaal, W.S.J. (author), Stelling, G.S. (author)
In this work, a comparison between the results of point-particle direct numerical simulations and PIV/PTV experiments of a particle-laden horizontal channel flow is presented. The numerical simulations were preformed trying to mimic as much as possible the experimental conditions. The accuracy of the point-particle approach was evaluated by...
conference paper 2006
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Prosser, R. (author)
In this paper we explore the specification of time dependent boundary conditions suitable for the simulation of low Mach number reacting flows. The standard treatments used to date are based on the method of characteristics, and essentially set to zero the incoming characteristics; this practise has been shown to have deleterious effects on the...
conference paper 2006
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Maher, G.D. (author), Hulshoff, S.J. (author)
The Variational Germano Identity [1, 2] is used to optimize the coefficients of residual-based subgrid-scale models that arise from the application of a Variational Multiscale Method [3, 4]. It is demonstrated that numerical iterative methods can be used to solve the Germano relations to obtain values for the parameters of subgrid-scale models...
conference paper 2014
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Thornber, B. (author), Drikakis, D. (author)
Simulations of three dimensional freely decaying homogeneous turbulence in a periodic cube have been used to examine in a detailed and quantitative manner the behaviour of a Large Eddy Simulation (LES) using implicit subgrid modelling. This paper details the form and behaviour of the implicit subgrid models for the Minmod and third order...
conference paper 2006
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Derakhshani, S.M. (author), Schott, D.L. (author), Lodewijks, G. (author)
Dust emissions can have significant effects on the human health, environment and industry equipment. Understanding the dust generation process helps to select a suitable dust preventing approach and also is useful to evaluate the environmental impact of dust emission. To describe these processes, numerical methods such as Computational Fluid...
conference paper 2013
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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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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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Khan, I.M. (author), Gilbert, T. (author), Barigou, M. (author)
The shape of the nozzle geometry is increasingly attractive in heating, ventilation and air conditioning applications. However an important consideration in the design of nozzle geometry is its effect on the dynamics of near flow field jet and to minimise the manufacturing cost for practical applications. In this investigation the effect of an...
conference paper 2006
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Dijkstra, J.T. (author), Uittenbogaard, R.E. (author), Stive, M.J.F. (author)
In many areas around the world, there is a large interest in the protection and restoration of aquatic vegetation, like eelgrass (Zostera marina), but little is known about the interaction of such vegetation with its environment. To improve this knowledge, a model has been developed that simulates this interaction between highly flexible...
conference paper 2006
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Campagne, G. (author), Cazalbou, J.B. (author), Joly, L. (author), Chassaing, P. (author)
In this paper, direct numerical simulation is used to study the interaction between turbulence and a free surface. The configuration is original due to the fact that a random force generates turbulence in the vicinity of a plane parallel to the free surface. Turbulence is therefore statistically steady and nearly isotropic at some distance of...
conference paper 2006
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Lee, J.I. (author), Kim, C. (author), Kim, K.H. (author)
The purpose of this paper is to develop an accurate analysis code for the flow of arc-heater by employing advanced numerical models. Governing equations are hyperbolic-type axisymmetric Navier-Stokes equations which include joule heating by arc, radiation and turbulent transport effect. Joule heating is simply calculated by Ohm’s law with the...
conference paper 2006
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Shekhar, C. (author), Nishino, K. (author), Iso, Y. (author)
The turbulence dissipation rate and turbulence shear stress are estimated inside a cylindrical, stirred flow mixer by carrying out Stereo PIV measurements in twelve vertical and three horizontal planes. The flow domain is vertically oriented, filled with the water. A commercially-available, three-blade impeller, HR-100, is used as the agitator....
conference paper 2013
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van Beinum, A.S. (author), Farah, H. (author), Wegman, F.C.M. (author), Hoogendoorn, S.P. (author)
Turbulence in traffic is a commonly known phenomenon, but the exact characteristics of this phenomenon are not yet clear. It reflects individual changes in speed, headways, and lanes in the traffic stream. The currently used freeway design guidelines prescribe different measures for handling turbulence, such as sufficient ramp spacing, and...
conference paper 2016
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