In this paper we consider superconvergence and supercloseness in the least-squares mixed finite element method for elliptic problems. The supercloseness is with respect to the standard and mixed finite element approximations of the same elliptic problem, and does not depend on the properties of the mesh. As an application, we will derive more precise a priori bounds for the least squares mixed ...

This work indicates a numerical study on the laminar heat transfer mixed convection in a square cavity with two openings (an inlet and an outlet) on vertical walls through which nanofluid flows. Two flow directions are examined: i) ascending flow which enters the bottom opening and exits the upper opening; ii) descending flow which enters the upper opening and exits the bottom opening. The asce...

Currently used finite volume methods are essentially low order methods. In this paper, we present a systematic way to derive higher order finite volume schemes from higher order mixed finite element methods. Mostly for convenience but sometimes from necessity, our procedure starts from the hybridization of the mixed method. It then approximates the inner product of vector functions by an approp...

in this study, focuses on applying the hp-version for forward modeling. the eit forward solver is normally based on the conventional finite element method (hfem). in h-fem, the polynomial order p of the element shape functions is constant and the element size h, is decreased. to accurately simulate the forward solution with the hfem, a mesh with large number of nodes and elements is usually need...

In this paper we show that mixed finite element methods for a fairly general second-order elliptic problem with variable coefficients can be given a nonmixed formulation. (Lower-order terms are treated, so our results apply also to parabolic equations.) We define an approximation method by incorporating some projection operators within a standard Galerkin method, which we call a projection fini...

We investigate the C interior penalty Galerkin (C IPG) method for biharmonic eigenvalue problems with the boundary conditions of the clamped plate, the simply supported plate and the Cahn-Hilliard type. We prove the convergence of the method and present numerical results to illustrate its performance. We also compare the C IPG method with the Argyris C finite element method, the Ciarlet-Raviart...

condition monitoring of bldc motors due to their important applications is gaining more and more significance. rotor eccentricity is one of the most important sources of faults in these motors. up to now, detection methods of this fault under nonstationary conditions are limited to complicated and time-consuming methods using wavelets and cohen class algorithms which are difficult to implement ...

The cracked Brazilian disc (CBD) specimen is widely used in order to determine mode-I/II and mixed-mode fracture toughness of a rock medium. In this study, the stress intensity factor (SIF) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (X-FEM). This method is based upon the finite element method (FEM). In this m...

This paper presents a Galerkin-based meshless method for calculating stress-intensity factors (SIFs) for a stationary crack in two-dimensional functionally graded materials of arbitrary geometry. The method involves an element-free Galerkin method (EFGM), where the material properties are smooth functions of spatial coordinates and two newly developed interaction integrals for mixed-mode fractu...

This article introduces and analyzes a weak Galerkin mixed finite element method for solving the biharmonic equation. The weak Galerkin method, first introduced by two of the authors (J. Wang and X. Ye) in [52] for second order elliptic problems, is based on the concept of discrete weak gradients. The method uses completely discrete finite element functions and, using certain discrete spaces an...