Enhanced Vertical Inhomogeneity in Turbulent Rotating Convection (2008)
Kunnen, R.P.J., Clercx, H.J.H., Geurts, B.J.
In this Letter we report experimental evidence that rotation enhances vertical inhomogeneity in turbulent convection, in spite of the increased columnar flow ordering under rotation. Measurements...
Kunnen, R.P.J., Clercx, H.J.H., Geurts, B.J., Akkermans, R.A.D., Verzicco, R.
Direct numerical simulation and stereoscopic particle image velocimetry of turbulent convection are used to gather spatial data for the calculation of structure functions. We wish to add to the...
Breakdown of large-scale circulation in turbulent rotating convection (2008)
Kunnen, R.P.J., Clercx, H.J.H., Geurts, B.J.
Turbulent rotating convection in a cylinder is investigated both numerically and experimentally at Rayleigh number Ra=109 and Prandtl number σ=6.4. In this letter we discuss two topics: the...
Turbulence modification by periodically modulated scale-dependent forcing (2008)
Kuczaj, A.K., Geurts, B.J., Lohse, D.
The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier–Stokes equations. The forcing is modulated via periodic energy-input variations at a...
Regularization modeling for LES of separated boundary layer flow (2008)
Regularization models for the turbulent stress tensor are applied to mixing and separated boundary layers. The Leray and the NS-a models in large-eddy simulation (LES) are compared to direct...
Reliability of LES in complex applications (2008)
The accuracy of large-eddy simulations is limited, among others, by the quality of the subgrid parameterisation and the numerical contamination of the smaller retained flow-structures. We review the...
Geurts, B.J., Kuczaj, A.K., Titi, E.S.
Inviscid regularization modeling of turbulent flow is investigated. Homogeneous, isotropic, decaying turbulence is simulated at a range of filter widths. A coarse-graining of turbulent flow arises...
Assessment of LES quality measures using the error landscape approach (2008)
Klein, M, Meyers, J, Geurts, B.J.
A large-eddy simulation database of homogeneous isotropic decaying turbulence is used to assess four different LES quality measures that have been proposed in the literature. The Smagorinsky subgrid...
Control over multiscale mixing in broadband-forced turbulence (2008)
The effects of explicit flow modulation on the dispersion of a passive scalar field are studied. Broadband forcing is applied to homogeneous isotropic turbulence to modulate the energy cascading and...
Based on the recently introduced variational multi-scale (VMS) approach to large-eddy simulation (LES) as introduced in [T.J.R. Hughes, L. Mazzei, K.E. Jansen, Large eddy simulation and the...
Meyers, J., Geurts, B.J., Sagaut, P.
We present a framework for the computational assessment and comparison of large-eddy simulation methods. We apply this to large-eddy simulation of homogeneous isotropic decaying turbulence using a...
Particle-Laden Flow From Geophysical to Kolmogorov Scales (2007)
Geurts, B.J., Clercx, H.J.H., Uijttewaal, W.S.J.
This book contains a selection of the papers that were presented at the EUROMECH colloquium on particle-laden flow held at the University of Twente in 2006. The multiscale nature of this challenging...
Modelling and controller design for a UV disinfection plant (2007)
Van Mourik, S., Geurts, B.J., Zwart, H.J.
A mathematical model describing fluid flow and concentration dynamics of microorganisms inside a UV photoreactor is developed. Using physical arguments and techniques from system theory, we...
Response maxima in time-modulated turbulence: Direct numerical simulations (2006)
Kuczaj, A.K., Geurts, B.J., Lohse, D.
The response of turbulent flow to time-modulated forcing is studied by direct numerical simulations of the Navier-Stokes equations. The large-scale forcing is modulated via periodic energy input...
Mixing in manipulated turbulence (2006)
A numerical investigation of turbulent flow, subject to deterministic broad-band forcing, is presented. Explicit forcing procedures are included that represent the simultaneous agitation of a wide...
Turbulence modification by periodically modulated scale-depending forcing (2006)
Kuczaj, A.K., Geurts, B.J., Lohse, D.
The response of turbulent flow to time-modulated forcing is studied by direct numerical simulation of the Navier-Stokes equations. The forcing is modulated via periodic energy input variations at a...
Dynamic self-organization in particle-laden channel flow (2006)
We study dynamic flow-structuring and mean-flow properties of turbulent particle-laden riser-flow at significant particle volume fractions of about 1.5%. We include particle–particle as well as...
Computational turbulent stress closure for large-eddy simulation of compressible flow (2006)
This paper studies the computation of stress tensors for turbulent compressible flow for purposes of subgrid modeling for LES (large eddy simulation) methods in an effort to provide a model closure....
We propose the successive inverse polynomial interpolation method to optimize model parameters in subgrid parameterization for large-eddy simulation. This approach is illustrated for the Smagorinsky...
Heat flux intensification by vortical flow localization in rotating convection (2006)
Kunnen, R.P.J., Clercx, H.J.H., Geurts, B.J.
The effect of rotation on turbulent convective flow between parallel plates has been assessed with direct numerical simulations. With increasing rotation-rate an interesting transition is observed in...
Optimal model parameters for multi-objective large-eddy simulations (2006)
Meyers, J., Sagaut, P., Geurts, B.J.
A methodology is proposed for the assessment of error dynamics in large-eddy simulations. It is demonstrated that the optimization of model parameters with respect to one flow property can be...
Interacting errors in large-eddy simulation: a review of recent developments (2006)
The accuracy of large-eddy simulations is limited, among others, by the quality of the subgrid parameterisation and the numerical contamination of the smaller retained flow structures. We review the...
Leray and LANS-$\alpha$ modeling of turbulent mixing (2006)
Mathematical regularization of the nonlinear terms in the Navier-Stokes equations is found to provide a systematic approach to deriving subgrid closures for numerical simulations of turbulent flow....
Commutator errors in large-eddy simulation (2006)
Commutator errors arise in large-eddy simulation of incompressible turbulent flow from the application of non-uniform filters to the continuity -- and Navier-Stokes equations. For non-uniform, high...
Decay or collapse: Aircraft wake vortices in grid turbulence (2006)
Ren, M., Elsenaar, A., Kuczaj, A.K., Geurts, B.J.
Trailing vortices are naturally shed by airplanes and they typically evolve into a counter-rotating vortex pair. Downstream of the aircraft, these vortices can persist for a very long time and extend...
Regularization modeling for large-eddy simulation of diffusion flames (2006)
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...
Magnitude control of commutator errors (2006)
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...
Development of regularization modeling and error-control in large-eddy simulation (2006)
Numerical simulation is developing into a viable research-tool to help understand dispersion and structure in turbulence. In order to make progress toward simulating flows under realistic...
A framework to assess the quality and robustness of LES codes (2006)
Meyers, J., Sagaut, P., Geurts, B.J.
We present a framework which can be used to rigourously assess and compare large-eddy simulation methods. We apply this to LES of homogeneous isotropic turbulence using three different...
Direct numerical simulation of turbulent rotating Rayleigh-Benard convection (2006)
Kunnen, R.P.J., Geurts, B.J., Clercx, H.J.H.
The influence of rotation on turbulent convection is investigated with direct numerical simulation. The classical Rayleigh-Benard con guration is augmented with steady rotation about the vertical...
Dynamic structuring and mixing efficiency in rapidly rotating shear layers (2006)
Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial...
A boundary element method for compound non-Newtonian drops (1997)
Toose, E.M., Geurts, B.J., Kuerten, J.G.M.
A boundary integral method for the simulation of the deformation of axisymmetric compound non-Newtonian drops suspended in a Newtonian fluid which is subjected to an axisymmetric flow eld is...
Natuur en technologie- hoe grondhoudingen de milieuproblematiek betekenis geven (1995)
Kockelkoren, P.J.H., Achterhuis, H.J., Smits, M.W., Geurts, B.J., Rip, A., Roelofs, E.E.
A boundary integral method for two-dimensional (non)-Newtonian drops in slow viscous flow (1995)
Toose, E.M., Geurts, B.J., Kuerten, J.G.M.
A boundary integral method for the simulation of the time-dependent deformation of Newtonian or non-Newtonian drops suspended in a Newtonian fluid is developed. The boundary integral formulation for...