Home About us Contact
|
Home About us Contact | ||
|
|
||
Solid Body (solid + body)
Selected AbstractsAdaptive embedded unstructured grid methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2004Rainald Löhner Abstract A simple embedded domain method for node-based unstructured grid solvers is presented. The key modification of the original, edge-based solver is to remove all geometry-parameters (essentially the normals) belonging to edges cut by embedded surface faces. Several techniques to improve the treatment of boundary points close to the immersed surfaces are explored. Alternatively, higher-order boundary conditions are achieved by duplicating crossed edges and their endpoints. Adaptive mesh refinement based on proximity to or the curvature of the embedded CSD surfaces is used to enhance the accuracy of the solution. User-defined or automatic deactivation for the regions inside immersed solid bodies is employed to avoid unnecessary work. Several examples are included that show the viability of this approach for inviscid and viscous, compressible and incompressible, steady and unsteady flows, as well as coupled fluid,structure problems. Copyright © 2004 John Wiley & Sons, Ltd. [source] Produktdesign , Möglichkeiten der ProduktgestaltungCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 8 2004W. Rähse Dr.-Ing.Article first published online: 29 JUL 200 Abstract Die Entwicklung leistungsstarker, auf den Anwendungsfall zugeschnittener Chemieprodukte erfolgt einerseits über gezielte Veränderungen am Molekül (Product Engineering) und andererseits über zugesetzte Hilfsstoffe, Formulierungen oder Mischungen (Product Design). Das Produktdesign umfasst zusätzlich die optimierte Produkthandhabung und Gestaltung. Es wird für Feststoffe an den Beispielen der Granulierung und des Coatings erläutert sowie konkret für die Qualitätseinstellung in der Papierindustrie und für die Gestaltung von Teigwaren diskutiert. Aus Schmelzen lassen sich über die Extrusionstechnologie beliebige Formen realisieren, z.,B. Folien, Stränge, Fasern, Hohl- bzw. Vollkörper (Flaschen, Rohre, Profile), oder über das Vertropfen/Versprühen entstehen Pulver, Granulate, Schuppen, Kügelchen und Pastillen. Für Flüssigkeiten erfolgt die Beschreibung der Einstellung gewünschter Produktleistungen am Beispiel der Niotenside, das Produktdesign am Beispiel der Milch und eines Öls. Die Kombination beider Produktdimensionen ist für die Lackindustrie dargestellt. Einige Gestaltungsmöglichkeiten von Suspensionen, Pasten und Lösungen werden an der Trocknung matrixverkapselter Enzyme, an der Zeolithherstellung sowie an der Verarbeitung keramischer Massen aufgezeigt. Product Design , Possibilities of Product Design The development of high-performance chemical products tailored to a concrete application is done either by making deliberate changes to a particular molecular structure (product engineering) or by adding auxiliary agents, formulations or mixtures (product design). Product design, besides the design proper, also includes the optimized application of the product. For solids it is exemplified by granulation and coating and discussed in concrete terms for the quality adjustment in the paper industry, and for the design of pasta products. Melts can take any desired shape when extruded, such as films, strands, fibers, hollow or solid bodies (bottles, tubes, sections) or they can be processed by dropping/spraying to produce powders, granulates, flakes, pearls or lozenges. The adjustment the desired properties for liquid products is described for the example of non-ionic surfactants and product design is shown for milk and for an oil. The combination of the two product dimensions is presented for the paint industry. Some design possibilities for suspensions, pastes and solutions are demonstrated by the drying of matrix-encapsulated enzymes, the production of zeolite and the processing of ceramic compounds. [source] All-cause mortality and fatal alcohol poisoning in Belarus, 1970,2005DRUG AND ALCOHOL REVIEW, Issue 5 2008YURY E. RAZVODOVSKY Abstract Introduction and Aims. Although alcohol appears to be an important contributor to the burden of disease in the countries of eastern Europe, little systematic research has been undertaken on its impact on mortality in the former Soviet republic of Belarus. There may be a number of factors underlying the particularly negative effect of alcohol on mortality in Belarus, including the pattern of drinking and use of surrogates. A solid body of research and empirical evidence suggests that hazardous patterns of alcohol consumption (binge drinking) lead to quicker and deeper intoxication, increasing the propensity for alcohol-related mortality. Design and Method. To estimate the aggregate level effect of binge drinking on the all-cause mortality rate, trends in the all-cause mortality and fatal alcohol poisoning rates (as a proxy for binge drinking) in Belarus from 1970 to 2005 were analysed employing AutoRegressive Integrated Moving Average (ARIMA) time,series analysis in order to assess a bivariate relationship between the two time,series. Results. The results of time,series analysis suggest a close relationship between all-cause mortality and fatal alcohol poisoning rates at the population level. Conclusions. This study supports the hypothesis that alcohol and all-cause mortality are connected closely in countries where the drinking culture is characterised by heavy drinking episodes and adds to the growing body of evidence that a substantial proportion of total mortality in Belarus is due to acute effects of binge drinking. [source] Distributed parameter thermal controllability: a numerical method for solving the inverse heat conduction problemINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2004Marios Alaeddine Abstract This paper addresses the inverse heat conduction problem encountered in thermal manufacturing processes. A numerical control algorithm is developed for distributed parameter conduction systems, based on Galerkin optimization of an energy index employing Green's functions. Various temperature profiles of variable complexity are studied, using the proposed technique, in order to determine the surface heat input distribution necessary to generate the desired temperature field inside a solid body. Furthermore, the effect of altering the iterative time step and duration of processing time, on the convergence of the solution generated by the aforementioned method is investigated. It is proved that despite the variations in numerical processing, the iterative technique is able to solve the problem of inverse heat conduction in the thermal processing of materials. Copyright © 2004 John Wiley & Sons, Ltd. [source] Fluid,solid interaction problems with thermal convection using the immersed element-free Galerkin methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2010Claudio M. Pita Abstract In this work, the immersed element-free Galerkin method (IEFGM) is proposed for the solution of fluid,structure interaction (FSI) problems. In this technique, the FSI is represented as a volumetric force in the momentum equations. In IEFGM, a Lagrangian solid domain moves on top of an Eulerian fluid domain that spans over the entire computational region. The fluid domain is modeled using the finite element method and the solid domain is modeled using the element-free Galerkin method. The continuity between the solid and fluid domains is satisfied by means of a local approximation, in the vicinity of the solid domain, of the velocity field and the FSI force. Such an approximation is achieved using the moving least-squares technique. The method was applied to simulate the motion of a deformable disk moving in a viscous fluid due to the action of the gravitational force and the thermal convection of the fluid. An analysis of the main factors affecting the shape and trajectory of the solid body is presented. The method shows a distinct advantage for simulating FSI problems with highly deformable solids. Copyright © 2009 John Wiley & Sons, Ltd. [source] A hybrid immersed boundary and material point method for simulating 3D fluid,structure interaction problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2008Anvar Gilmanov Abstract A numerical method is developed for solving the 3D, unsteady, incompressible Navier,Stokes equations in curvilinear coordinates containing immersed boundaries (IBs) of arbitrary geometrical complexity moving and deforming under forces acting on the body. Since simulations of flow in complex geometries with deformable surfaces require special treatment, the present approach combines a hybrid immersed boundary method (HIBM) for handling complex moving boundaries and a material point method (MPM) for resolving structural stresses and movement. This combined HIBM & MPM approach is presented as an effective approach for solving fluid,structure interaction (FSI) problems. In the HIBM, a curvilinear grid is defined and the variable values at grid points adjacent to a boundary are forced or interpolated to satisfy the boundary conditions. The MPM is used for solving the equations of solid structure and communicates with the fluid through appropriate interface-boundary conditions. The governing flow equations are discretized on a non-staggered grid layout using second-order accurate finite-difference formulas. The discrete equations are integrated in time via a second-order accurate dual time stepping, artificial compressibility scheme. Unstructured, triangular meshes are employed to discretize the complex surface of the IBs. The nodes of the surface mesh constitute a set of Lagrangian control points used for tracking the motion of the flexible body. The equations of the solid body are integrated in time via the MPM. At every instant in time, the influence of the body on the flow is accounted for by applying boundary conditions at stationary curvilinear grid nodes located in the exterior but in the immediate vicinity of the body by reconstructing the solution along the local normal to the body surface. The influence of the fluid on the body is defined through pressure and shear stresses acting on the surface of the body. The HIBM & MPM approach is validated for FSI problems by solving for a falling rigid and flexible sphere in a fluid-filled channel. The behavior of a capsule in a shear flow was also examined. Agreement with the published results is excellent. Copyright © 2007 John Wiley & Sons, Ltd. [source] High-order stable interpolations for immersed boundary methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2006Nikolaus Peller Abstract The analysis and improvement of an immersed boundary method (IBM) for simulating turbulent flows over complex geometries are presented. Direct forcing is employed. It consists in interpolating boundary conditions from the solid body to the Cartesian mesh on which the computation is performed. Lagrange and least squares high-order interpolations are considered. The direct forcing IBM is implemented in an incompressible finite volume Navier,Stokes solver for direct numerical simulations (DNS) and large eddy simulations (LES) on staggered grids. An algorithm to identify the body and construct the interpolation schemes for arbitrarily complex geometries consisting of triangular elements is presented. A matrix stability analysis of both interpolation schemes demonstrates the superiority of least squares interpolation over Lagrange interpolation in terms of stability. Preservation of time and space accuracy of the original solver is proven with the laminar two-dimensional Taylor,Couette flow. Finally, practicability of the method for simulating complex flows is demonstrated with the computation of the fully turbulent three-dimensional flow in an air-conditioning exhaust pipe. Copyright © 2006 John Wiley & Sons, Ltd. [source] Influence of transverse rotating magnetic field on enhancement of solid dissolution processAICHE JOURNAL, Issue 6 2010Rakoczy Abstract The main objective of this work is to study the effect of transverse rotating magnetic field (TRMF) on the enhancement of solid dissolution process in the novel type reactor (TRMFR). The application of magnetically driven fluidization (MDF with homogeneous and heterogeneous systems) on mass transfer process is presented. A study of the effect of ferromagnetic particles content on solid,liquid mass transfer has been made. The experimental investigations are provided for the explanation of the influence on the dissolution process of a solid body to surrounding its dilute solution in a novel type reactor with the ferromagnetic particles suspended. The mass transfer coefficient is calculated from a kinetic equation and correlated in the relationship including standard and magnetic dimensionless numbers. The overall enhancements due to TRMF and MDF were compared. Unique correlating relations were obtained to generalize the experimental database. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] | |||||||||||||