scholarly journals A Monolithic Finite Element Formulation for Magnetohydrodynamics Involving a Compressible Fluid

Fluids ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 27
Author(s):  
Adhip Gupta ◽  
C. S. Jog
Keyword(s):  
Finite Element ◽  
Compressible Fluid ◽  
Three Dimensional ◽  
Benchmark Problems ◽  
Element Formulation ◽  
Coarse Mesh ◽  
Exact Linearization ◽  
Pressure Formulation ◽  
Physical Variables ◽  
Velocity Pressure

This work develops a new monolithic finite-element-based strategy for magnetohydrodynamics (MHD) involving a compressible fluid based on a continuous velocity–pressure formulation. The entire formulation is within a nodal finite element framework, and is directly in terms of physical variables. The exact linearization of the variational formulation ensures a quadratic rate of convergence in the vicinity of the solution. Both steady-state and transient formulations are presented for two- and three-dimensional flows. Several benchmark problems are presented, and comparisons are carried out against analytical solutions, experimental data, or against other numerical schemes for MHD. We show a good coarse-mesh accuracy and robustness of the proposed strategy, even at high Hartmann numbers.

scholarly journals Stress Analysis by Two Cuboid Isoparametric Elements

2019 ◽  
Author(s):  
Mohammad Rezaiee-Pajand ◽  
Arash Karimipour
Keyword(s):  
Finite Element ◽  
Stress Responses ◽  
Stress Function ◽  
Three Dimensional ◽  
Elastic Field ◽  
Benchmark Problems ◽  
Element Formulation ◽  
Field Equations ◽  
Structural Problems ◽  
Isoparametric Elements

The finite element method is a powerful tool for solving most of the structural problems. This technique has been used extensively, since the complexity of the elastic field equations does not allow the specialist to find analytical solutions, especially for the three-dimensional structures. It is well-known that the finite element formulation yields the approximate stress responses. To remedy this defect, the Airy stress function is utilized in this study. The stress function formulation leads to a valid solution since it satisfies equilibrium and compatibility equations simultaneously. Two cuboid isoparametric elements are formulated for solving three-dimensional elastic structures. To demonstrate the performance of the proposed technique, various benchmark problems are analyzed. The errors between the exact, displacement-based finite element and recommended scheme solution are also calculated. All the obtained outcomes show the good merit of the presented new elements.

scholarly journals Finite Element Formulation of Fractional Constitutive Laws Using the Reformulated Infinite State Representation

2021 ◽  
Vol 5 (3) ◽  
pp. 132
Author(s):  
Matthias Hinze ◽  
André Schmidt ◽  
Remco I. Leine
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Constitutive Law ◽  
Benchmark Problems ◽  
Element Formulation ◽  
Algebraic Equations ◽  
State Representation ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Infinite State

In this paper, we introduce a formulation of fractional constitutive equations for finite element analysis using the reformulated infinite state representation of fractional derivatives. Thereby, the fractional constitutive law is approximated by a high-dimensional set of ordinary differential and algebraic equations describing the relation of internal and external system states. The method is deduced for a three-dimensional linear viscoelastic continuum, for which the hydrostatic and deviatoric stress-strain relations are represented by a fractional Zener model. One- and two-dimensional finite elements are considered as benchmark problems with known closed form solutions in order to evaluate the performance of the scheme.

scholarly journals Polygonal finite elements for three-dimensional Voronoi-cell-based discretisations

2012 ◽  
Author(s):  
Kaliappan Jayabal ◽  
Andreas Menzel
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Three Dimensional ◽  
Specific Property ◽  
Voronoi Cell ◽  
Polycrystalline Materials ◽  
Element Formulation ◽  
Hybrid Finite Element ◽  
Grain Structures ◽  
Polygonal Elements

Hybrid finite element formulations in combination with Voronoi-cell-based discretisation methods can efficiently be used to model the behaviour of polycrystalline materials. Randomly generated three-dimensional Voronoi polygonal elements with varying numbers of surfaces and corners in general better approximate the geometry of polycrystalline microor rather grain-structures than the standard tetrahedral and hexahedral finite elements. In this work, the application of a polygonal finite element formulation to three-dimensional elastomechanical problems is elaborated with special emphasis on the numerical implementation of the method and the construction of the element stiffness matrix. A specific property of Voronoi-based discretisations in combination with a hybrid finite element approach is investigated. The applicability of the framework established is demonstrated by means of representative numerical examples.

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