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- Akkerman, I. (author), Hulshoff, S.J. (author) report 2005
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Munts, E.A. (author)The Variational Multiscale (VMS) method has appeared as a promising new approach to the Large Eddy Simulation (LES) of turbulent flows. The key advantage of the VMS approach is that it allows different subgrid-scale (SGS) modeling assumptions to be made at different ranges of the resolved scales. Typically, in the VMS method, SGS modeling is...doctoral thesis 2006
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John, V. (author), Tambulea, A. (author)Two realizations of finite element variational multiscale (VMS) methods for the simulation of incompressible turbulent flows are studied. The difference between the two approaches consists in the way the spaces for the large scales and the resolved small scales are chosen. The paper addresses issues of the implementation of these methods, the...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 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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Lube, G. (author)The numerical solution of the nonstationary, incompressible Navier-Stokes model can be split into linearized auxiliary problems of Oseen type. We present in a unique way different stabilization techniques of finite element schemes on isotropic and hybrid meshes. First we describe the state-of-the-art for the classical residual-based SUPG/PSPG...conference paper 2006
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Trebotich, D. (author), Miller, G.H. (author), Bybee, M.D. (author)We present a new method for particle interactions in polymer models of DNA. The DNA is represented by a bead-rod polymer model. The main objective in this work is to implement short range forces to properly model polymer-polymer and polymer-surface interactions. We will discuss two methods for these interactions: (1) a new rigid constraint...conference paper 2006
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Winckelmans, G. (author), Cocle, R. (author), Dufresne, L. (author), Capart, R. (author), Bricteux, L. (author), Daeninck, G. (author), Lonfils, T. (author), Duponcheel, M. (author), Desenfans, O. (author), Georges, L. (author)This paper aims at presenting DNS and LES as applied to the simulation of vortex wakes: in laboratory conditions (moderate to medium Reynolds numbers) and up to real aircraft conditions (high to very high Reynolds numbers). Only incompressible flows are considered. DNS and LES are able to capture complex 3-D physics provided one uses high...conference paper 2006
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Toxopeus, G. (author)An optimal use of shared-earth modeling is hampered by the fact that simulating a migrated image that can be compared directly to the real migrated image is time-consuming. The key to enable iterative testing of different geological scenarios is to filter a shared-earth model by a spatial resolution filter to simulate a migrated image. The...doctoral thesis 2006
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Conradi, I.M. (author)Recently, Calo [V.M. Calo, Residual-based multiscale turbulence modeling, PhD thesis, Stanford University, 2004] devised the so-called residual-based variational multiscale (RB-VMS) formulation for large-eddy simulation, that uses both the scale separation and the coupling terms in the variational multiscale equations. Using arguments from...master thesis 2007
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Akkerman, I. (author), Bazilevs, Y. (author), Calo, V.M. (author), Hughes, T.J.R. (author), Hulshoff, S. (author)This paper examines the role of continuity of the basis in the computation of turbulent flows. We compare standard finite elements and non-uniform rational B-splines (NURBS) discretizations that are employed in Isogeometric Analysis (Hughes et al. in Comput Methods Appl Mech Eng, 194:4135–4195, 2005). We make use of quadratic discretizations...journal article 2007
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Akkerman, I. (author)A Residual-Based Large-Eddy Simulation (RB-LES) method is developed. This is done by discretizing the Navier-Stokes equations directly. A priori filtering is omitted. Analytical approximation of the subgrid scales results in a unusually-stabilized finite-element method with additional terms arising due to the nonlinearity. This RB-LES method is...doctoral thesis 2009
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Nguyen, V.P. (author), Stroeven, M. (author), Sluys, L.J. (author)In this contribution, we present the mechanical behaviour of the hardening cement paste explicitly taking into account its complex microstructure. The microstructure of the cement paste is obtained via numerical cement hydration simulation. A simple nonlocal isotropic damage model is adopted for different constituents of the cement paste. The...conference paper 2009
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Lloberas Valls, O. (author), Rixen, D.J. (author), Simone, A. (author), Sluys, L.J. (author)In this contribution we describe a methodology for the study of softening brittle materials at different scales of observation. The goal is to account for a higher resolution at those areas that undergo the non-linear processes. We apply the FETI (Finite Element Tearing and Interconnecting) technique to glue different domain resolutions during...conference paper 2009
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Verhoosel, C.V. (author)Micro electromechanical systems (MEMS) are nowadays used in many applications, such as airbag accelerometers and inkjet printer heads. With the number of applications growing, the need for advanced numerical tools to aid in the design of MEMS increases. The development of such tools is far from trivial, since numerical modelling of MEMS poses...doctoral thesis 2009
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Van Esch, J.M. (author)Natural geological formations generally show multiscale structural and functional heterogeneity evolving over many orders of magnitude in space and time. In subsurface hydrological simulations the geological model focuses on the structural hierarchy of physical sub units and the flow model addresses the functional hierarchy of the flow process....doctoral thesis 2010
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Lloberas Valls, O. (author), Rixen, D.J. (author), Simone, A. (author), Sluys, L.J. (author)In this contribution we describe a methodology for the multiscale analysis of heterogeneous quasi-brittle materials. The algorithm is based on the finite element tearing and interconnecting FETI [1] method cast in a non-linear setting. Adaptive multiscale analysis is accounted for with the use of selective refinement at domains that undergo...conference paper 2011
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Nguyen, V.P. (author)The conventional multiscale homogenization theory, which has mainly been applied to determine constitutive laws for bulk materials, suffers from two drawbacks when applied to softening materials. Firstly, the coarse scale response is sensitive to the finite element mesh used to discretize the coarse scale domain. Secondly, increasing the size of...doctoral thesis 2011
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Qian, Z. (author), Schlangen, E. (author), Ye, G. (author), Van Breugel, K. (author)Cracking in cement-based materials is usually not easy to predict, because of the complexity of their microstructures. Concrete is a composite material of mortar and coarse aggregates, and mortar consists of cement paste and sands. The fracture processes in these materials are related, and this paper aims to reveal the relationship by developing...conference paper 2012
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Socha, W. (author)This short summary helps to grasp the motive behind the research, its objectives and to find out what is presented on the following pages of the report. It offers a condensed, one page recapitulation of its contents and intentions and suggests who might be interested to read it. CONTEXT Map generalisation is a tedious task, requiring skilled...master thesis 2012