1,723,482 research outputs found
Co-ordinate transforms underpin multiscale modelling and reduction in deterministic and stochastic systems
Full text linkA persistent feature of complex systems in engineering and science is the emergence of macroscopic, coarse grained, coherent behaviour from microscale interactions. In current modeling, ranging from ecology to materials science, the underlying microscopic mechanisms are known, but the closures to translate microscale knowledge to a large scale macroscopic description are rarely available in closed form. Kevrekidis proposes new 'equation free' computational methodologies to circumvent this stumbling block in multiscale modelling. Nonlinear coordinate transforms underpin analytic techniques that support these computational methodologies. But to do so we must cross multiple space and time scales, in both deterministic and stochastic systems, and where the microstructure is either smooth or detailed. Using examples, I describe progress in using nonlinear coordinate transforms to illuminate such multiscale modelling issues
Multiscale modelling of interface fracture
No full textDescribes the multiscale modelling of an interface fracture
Discrete Element Method for Multiscale Modelling
No full textA discrete element method (DEM) has been developed to provide highly accurate and detailed predictions of the Lagrangian particle phase. Especially in this study, DEM has been used together with an Eulerian approach for the fluid phase to look at interphase exchange phenomena in a multiphase-multiscale modeling approach. The drying process inside a fluidized bed coffee bean roaster has been chosen. Herein, heat, mass, and momentum transport are solved on a fluid cell level; heat, mass, and momentum transfer coefficients are solved at a particle scale level; and 1D temperature and moisture content profiles are solved inside each coffee bean on a sub-particle scale level. Therefore, this multiscale approach provides much more information compared to existing coffee bean roaster models. In this work, a detailed description of this method is provided and results on different scale levels have been discussed. Modeling data and experimental results are compared and found to be in good agreement
Multiscale modelling of engineering materials
No full textOutline of multiscale modelling and the process-structure-properties-performance (PSPP) concept is presented. Brief description of multiscale modelling methods is provided following their range of application in spatial and temporal ranges. The PSPP concept as a state-of-the-art modelling assisted material design procedure is described. Case examples illustrating the material features incorporated to a PSPP analysis are given, emphasizing the modelling of realistic material structures in the nano to microstructure range and on the other hand the mechanisms responsible for material performance in a component environment
Multiscale modelling of engineering materials
No full textOutline of multiscale modelling and the process-structure-properties-performance (PSPP) concept is presented. Brief description of multiscale modelling methods is provided following their range of application in spatial and temporal ranges. The PSPP concept as a state-of-the-art modelling assisted material design procedure is described. Case examples illustrating the material features incorporated to a PSPP analysis are given, emphasizing the modelling of realistic material structures in the nano to microstructure range and on the other hand the mechanisms responsible for material performance in a component environment
Challenges in multiscale modelling and its application to granulation systems
No full textSince the mid 1990s there has been an increasing recognition of chemical engineering's multiscale nature. Multiscale modelling attempts to create flexible and efficient models by linking two or more partial models that describe phenomena at different characteristic length and time scales. In the first part of this paper, we briefly review multiscale modelling in chemical engineering. Three key tasks used in multiscale modelling are identified, and the current practices and unresolved issues in each are discussed. The second part of the paper examines the modelling of a wet granulation circuit from a multiscale perspective. A 'scale map' for drum granulation is proposed to assist in visualising the multiscale nature of the system. The three multiscale modelling tasks are considered in turn and some suggestions for modelling are proposed. Through this paper we are seeking to promote discussion on multiscale modelling and to receive feedback on its application to granulation
Staggered grids for multidimensional multiscale modelling
No full textAvailable online 10 January 2024For high accuracy and to improve simulated wave characteristics, this article extends the concept of staggered grids to novel multidimensional multiscale modelling enabling efficient computation on sparse patches. Computational schemes for wave-like systems with small dissipation are often inaccurate and unstable due to truncation errors and numerical roundoff errors. Hence simulations of wave-like systems lacking proper handling of these numerical issues often fail to represent the physical characteristics of wave phenomena. This challenge gets even more intricate for multiscale modelling, especially in multiple dimensions. But numerical schemes on staggered grids are significantly less dispersive, better model the group velocity, and preserve much of the wave characteristics. This article develops and exhaustively studies all 167 040 possible 2D multiscale staggered grids. Our catalog (Divahar, 2023) interactively plots all of them. Only 120 multiscale staggered patch grids give stable and accurate multiscale schemes. Specifically, this article develops these 120 multiscale staggered grids and demonstrates their stability, accuracy, and wave-preserving characteristic for equation-free multiscale modelling of weakly damped linear waves. These characteristics of the developed multiscale staggered grids must also hold in general for multiscale modelling of many complex spatio-temporal physical phenomena such as the general computational fluid dynamics.J. Divahar, A.J. Roberts, Trent W. Mattner, J.E. Bunder, Ioannis G. Kevrekidi
Multiscale modelling of mechanical and flow performance of nonwovens
Full text linkMultiscale modelling of mechanical and flow performance of nonwoven
Concurrent Multiscale Modelling of Three Dimensional Crack and Dislocation Propagation
No full textConcurrent Multiscale Modelling of Three Dimensional Crack and Dislocation Propagatio
Multiscale modelling of mechanical and flow performance of nonwovens
No full textMultiscale modelling of mechanical and flow performance of nonwoven
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