Τμήμα Μηχανικών Μηχανολογίας και Κατασκευαστικής / Department of Mechanical and Manufacturing Engineering: Recent submissions
Now showing items 1001-1020 of 1036
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Conference Object
Rheology of semisolid suspensions
(Affiliation: Semisolid Processing Laboratory, Metal Processing Institute, WPI, Worcester, MA 01609, United StatesAffiliation: Polytech. University of Puerto Rico, Mechanical Engineering Department, San Juan 00918, Puerto RicoAffiliation: Institute for Problems in Mechanics, Russian Academy of Science, pr. Vemadskogo, 101, 117526 Moscow, Russian FederationCorrespondence Address: Alexandrou, A.N.Semisolid Processing Laboratory, Metal Processing Institute, WPI, Worcester, MA 01609, United States, 2000)The effective use of the semisolid process presumes a good theoretical framework to describe it. The understanding of semisolid behavior should be based upon a combination of basic and empirical knowledge in versatile ...
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Article
Injection molding using a generalized eulerian lagrangian formulation
(1993)A mathematical and a numerical approach to model the injection mold filling stage is presented. The approach is based on a Generalized Eulerian Lagrangian (GEL) formulation. In purely Lagrangian formulations the solution ...
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Article
Mathematical and computational modeling of die filling in semisolid metal processing
(1999)A 'Bingham type', or Herschel-Bulkley constitutive relation capable of describing correctly the bulk behavior of the semisolid slurry is introduced. This relation is implemented in a modified version of the casting simulation ...
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Article
The use of generalized eulerian–lagrangian formulations in composite materials processing
(1994)The advantages of the Generalized Eulerian–Lagrangian (GEL) formulations in modeling and numerical solution of unsteady flow of fiber suspensions are discussed. This formulation offers the flexibility of selectively applying ...
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Conference Object
Inverse finite element method for directly formulated free and moving boundary problems
(Publ by Computational Mechanics Publ, 1991)In free boundary problems a priori unknown geometric parameters need to be evaluated simultaneously with the primary field unknowns. These problems are highly nonlinear and difficult to handle computationally. Here an ...
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Article
A consistent velocity approximation for variable-density flow and transport in porous media
(2013)Using a finite-volume nodal-based code, we introduce a new consistent numerical scheme for approximating the seepage velocity in variable-density flow in porous media. It has been known from previous works that the lack ...
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Conference Object
Three dimensional flow of thixotropic materials in a channel with a sudden expansion using a phenomenological constitutive relation
(Affiliation: WPI, Worcester, United StatesCorrespondence Address: Alexandrou, Andreas N.WPI, Worcester, United States, 1996)A constitutive relation is proposed that is capable of predicting a wide range of experimental rheological behavior depending on the proper choice of the parameters. The model represents the otherwise discontinuous Bingham ...
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Article
Effects of the consistency of the fringing magnetic field on direct numerical simulations of liquid-metal flow
(2011)We investigate the effects of the consistency of strong fringing decreasing magnetic fields on numerical simulations of classical experimental data. Studies about fringing magnetic fields have attracted the attention of ...
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Article
Full magnetohydrodynamic solution of liquid-metal flow in an insulating pipe subjected to a strong fringing magnetic field
(2012)This paper addresses liquid-metal flow under a strong, fringing, decreasing magnetic field in an insulating circular pipe by a full resolution of the magnetohydrodynamic (MHD) equations. The aims of the paper are first to ...
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Article
On the modeling of semisolid suspensions
(2008)Due to the distinct rheology of semisolid slurries the process has well established advantages over competing near-net-shape manufacturing technologies. Despite the obvious advantages of the process its adoption by the ...
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Article
Numerical simulation of a liquid-metal flow in a poorly conducting pipe subjected to a strong fringing magnetic field
(2018)Using high resolution numerical simulations, we study the flow of a liquid metal in a pipe subjected to an intense decreasing magnetic field (fringing magnetic field). The chosen flow parameters are such that our study is ...
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Article
An inverse finite element method for directly formulated free boundary problems
(1989)In free boundary problems, in addition to the primary field variables, velocity, pressure and temperature, unknown geometric parameters need to be evaluated. A characteristic feature of the problems is a demarcation line ...
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Conference Object
Compression molding of semi-concentrated fiber suspensions: Flow and fiber orientation
(Publ by ASME, 1993)The focus of this paper is compression molding of semi-concentrated fiber suspensions. During compression molding a premeasured amount of raw material (charge) is placed between two halves of a die. The die is then closed ...
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Article
On the linear stability of turbulent plane strain flow in a rotating frame
(2007)We apply inviscid rapid distortion theory to the limiting hyperbolic case of turbulent plain strain flow in a rotating frame and investigate the dependence of the evolution of the turbulent kinetic energy on the frame ...
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Article
Compression molding using a generalized eulerian–lagrangian formulation with automatic remeshing
(1992)A generalized Eulerian‐Lagrangian approach is used to study the compression molding of viscoelastic polymers. The complete, unsteady, two‐dimensional equations of motion are used in the analysis. The White–Metzner model ...
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Article
Direct numerical simulation of turbulent liquid metal flow entering a magnetic field
(2013)This paper presents direct numerical simulations (DNS) of fully developed turbulent liquid-metal flow in a circular duct entering a magnetic field. The case of a magnetohydrodynamic flow leaving a strong magnetic field has ...
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Article
Rapid shear of initially anisotropic turbulence in a rotating frame?
(2007)In the present study, we investigate, using inviscid rapid distortion theory, the evolution of sheared turbulence in a rotating frame as a function of the rotation rate (including stable, transitional, and unstable regimes), ...
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Article
An analytical solution for rapidly distorted turbulent shear flow in a rotating frame
(2006)In this study we apply rapid distortion theory to the case of nonstratified homogeneous turbulence that is sheared in a frame that counter-rotates at a rate that matches in magnitude the rotation associated with the mean ...
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Conference Object
Processing of semi-solid materials using a shear-thickening Bingham fluid model
(Publ by ASME, 1994)Recently the importance of processing metals and metal matrix composites in semi-solid state is growing rapidly. Performing the shape making operations in the semi-solid state provides a better opportunity to control the ...
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Article
Unsteady flow of semi-concentrated suspensions using finite deformation tensors
(1994)The interest in the theoretical investigation of the flow behavior of fiber suspensions during manufacturing processes has increased considerably due to the increased interest in the use of composite materials. The unsteady ...