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Interface Position (interface + position)
Selected AbstractsComputation of mould filling processes with a moving Lagrangian interface techniqueINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 7 2002Marcela Cruchaga Abstract Computation of non-isothermal flow problems involving moving interfaces is presented. A Lagrangian interface technique, defined in the context of a fixed-mesh finite element formulation for incompressible flows, is employed to update the interface position. A global mass-corrector algorithm is used to accurately enforce the global mass conservation. The Navier,Stokes equations are solved with an improved sub-element integration technique to more accurately account for sudden changes in the fluid properties across the interface. The method described is applied to two mould filling problems. Copyright © 2002 John Wiley & Sons, Ltd. [source] On the optimal cooling strategy for variable-speed continuous castingINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2002D. Constales Abstract In this paper, we consider the inverse problem of determining the optimal cooling parameters for continuous casting under changing casting speed. We rely on automatic differentiation to support different search methods for the parameter values that will minimize a given cost functional, which can include a variety of criteria: surface temperature evolution and variation, interface position, full solidification point. In the direct problem we use a fixed-domain transformation to solve the corresponding free-boundary problem to high accuracy. Numerical experiments are provided to illustrate and support the effectiveness of the present concept. Copyright © 2001 John Wiley & Sons, Ltd. [source] SOLID FOODS FREEZE-DRYING SIMULATION AND EXPERIMENTAL DATAJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2005S. KHALLOUFI ABSTRACT This article presents a mathematical model describing the unsteady heat and mass transfer during the freeze drying of biological materials. The model was built from the mass and energy balances in the dried and frozen regions of the material undergoing freeze drying. A set of coupled nonlinear partial differential equations permitted the description of the temperature and pressure profiles, together with the position of the sublimation interface. These equations were transformed to a finite element scheme and numerically solved using the Newton-Raphson approach to represent the nonlinear problem and the interface position. Most parameters involved in the model (i.e., thermal conductivity, specific heat, density, heat and mass transfer coefficients etc.) were obtained from experimental data cited in the literature. The dehydration kinetics and the temperature profiles of potato and apple slabs were experimentally determined during freeze drying. The simulation results agreed closely with the water content experimental data. The prediction of temperature profiles within the solid was, however, less accurate. [source] Multi-material incompressible flow simulation using the moment-of-fluid method,INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2010Samuel P. Schofield Abstract This paper compares the numerical performance of the moment-of-fluid (MOF) interface reconstruction technique with Youngs, LVIRA, power diagram (PD), and Swartz interface reconstruction techniques in the context of a volume-of-fluid (VOF) based finite element projection method for the numerical simulation of variable-density incompressible viscous flows. In pure advection tests with multiple materials MOF shows dramatic improvements in accuracy compared with the other methods. In incompressible flows where density differences determine the flow evolution, all the methods perform similarly for two material flows on structured grids. On unstructured grids, the second-order MOF, LVIRA, and Swartz methods perform similarly and show improvement over the first-order Youngs' and PD methods. For flow simulations with more than two materials, MOF shows increased accuracy in interface positions on coarse meshes. In most cases, the convergence and accuracy of the computed flow solution was not strongly affected by interface reconstruction method. Published in 2009 by John Wiley & Sons, Ltd. [source] | ||||||||||