MFEMMassKernel

Overview

Adds the domain integrator for integrating the bilinear form

var element = document.getElementById("moose-equation-440c0fe8-a0ab-43ca-8e48-f9692700ffbb");katex.render("(k u, v)_\\Omega \\,\\,\\, \\forall v \\in V", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});

where $var element = document.getElementById("moose-equation-9cdd4dc4-0420-4807-bcab-bf36457e8fab");katex.render("u, v \\in H^1", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ and $var element = document.getElementById("moose-equation-66961d96-439f-45f9-841f-d0d3fa4357b3");katex.render("k", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is a scalar mass coefficient.

This term arises from the weak form of the mass operator

var element = document.getElementById("moose-equation-5abb61a3-f417-416f-a60e-9fc4a89e8f9b");katex.render("k u", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});

Input Parameters

blockThe list of subdomains (names or ids) that this object will be restricted to. Leave empty to apply to all subdomains.
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of subdomains (names or ids) that this object will be restricted to. Leave empty to apply to all subdomains.
coefficient1.Name of property for the mass coefficient k. A functor is any of the following: a variable, an MFEM material property, a function, a postprocessor or a number.
Default:1.
C++ Type:MFEMScalarCoefficientName
Controllable:No
Description:Name of property for the mass coefficient k. A functor is any of the following: a variable, an MFEM material property, a function, a postprocessor or a number.
variableVariable labelling the weak form this kernel is added to
C++ Type:VariableName
Unit:(no unit assumed)
Controllable:No
Description:Variable labelling the weak form this kernel is added to

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:No
Description:Set the enabled status of the MooseObject.

Advanced Parameters

Input Files

(test/tests/mfem/complex/complex.i)
(test/tests/mfem/submeshes/boundary_submesh.i)

Child Objects

(framework/include/mfem/kernels/MFEMTimeDerivativeMassKernel.h)

(test/tests/mfem/complex/complex.i)

mu = 1.0
epsilon = 1.0
sigma = 20.0
omega = 10.0
kappa_r = 12.7201964951406889525742371916
kappa_i = -7.86151377757423297509831172647

[Mesh]
  type = MFEMMesh
  file = ../mesh/inline-quad.mesh
  dim = 2
[]

[Problem]
  type = MFEMProblem
  numeric_type = complex
[]

[FESpaces]
  [H1FESpace]
    type = MFEMScalarFESpace
    fec_type = H1
    fec_order = FIRST
  []
[]

[Variables]
  [u]
    type = MFEMComplexVariable
    fespace = H1FESpace
  []
[]

[Functions]
  [u0_r]
    type = ParsedFunction
    expression = exp(y*${kappa_i})*cos(y*${kappa_r})
  []
  [u0_i]
    type = ParsedFunction
    expression = -exp(y*${kappa_i})*sin(y*${kappa_r})
  []
  [stiffnessCoef]
    type = ParsedFunction
    expression = 1.0/${mu}
  []
  [massCoef]
    type = ParsedFunction
    expression = -${omega}*${omega}*${epsilon}
  []
  [lossCoef]
    type = ParsedFunction
    expression = ${omega}*${sigma}
  []
[]

[BCs]
  [dbc]
    type = MFEMComplexScalarDirichletBC
    variable = u
    coefficient_real = u0_r
    coefficient_imag = u0_i
  []
[]

[Kernels]
  [diffusion_complex]
    type = MFEMComplexKernel
    variable = u
    [RealComponent]
      type = MFEMDiffusionKernel
      coefficient = stiffnessCoef
    []
    [ImagComponent]
      type = MFEMDiffusionKernel
      coefficient = 0.0
    []
  []
  [mass_complex]
    type = MFEMComplexKernel
    variable = u
    [RealComponent]
      type = MFEMMassKernel
      coefficient = massCoef
    []
    [ImagComponent]
      type = MFEMMassKernel
      coefficient = lossCoef
    []
  []
[]

[Solver]
  type = MFEMSuperLU
[]

[Executioner]
  type = MFEMSteady
  assembly_level = legacy
[]

[Outputs]
  [ParaViewDataCollection]
    type = MFEMParaViewDataCollection
    file_base = OutputData/Complex2DQuad
    vtk_format = ASCII
  []
[]

(test/tests/mfem/submeshes/boundary_submesh.i)

[Mesh]
  type = MFEMMesh
  file = ../mesh/cylinder-hex-q2.gen
  uniform_refine = 1
[]

[Problem]
  type = MFEMProblem
[]

[SubMeshes]
  [exterior]
    type = MFEMBoundarySubMesh
    boundary = curved_surface
  []
[]

[FESpaces]
  [SubMeshH1FESpace]
    type = MFEMGenericFESpace
    fec_name = H1_2D_P1
    submesh = exterior
  []
[]

[Variables]
  [submesh_potential]
    type = MFEMVariable
    fespace = SubMeshH1FESpace
  []
[]

[Kernels]
  [mass]
    type = MFEMMassKernel
    variable = submesh_potential
  []
  [source]
    type = MFEMDomainLFKernel
    variable = submesh_potential
    coefficient = 3.0
  []
[]

[Preconditioner]
  [boomeramg]
    type = MFEMHypreBoomerAMG
  []
[]

[Solver]
  type = MFEMHypreGMRES
  preconditioner = boomeramg
  l_tol = 1e-8
  l_max_its = 1000
[]

[Executioner]
  type = MFEMSteady
  device = cpu
[]

[Outputs]
  [ParaViewDataCollection]
    type = MFEMParaViewDataCollection
    file_base = OutputData/BoundaryPotential
    vtk_format = ASCII
    submesh = exterior
  []
[]

(framework/include/mfem/kernels/MFEMTimeDerivativeMassKernel.h)

// This file is part of the MOOSE framework
// https://mooseframework.inl.gov
//
// All rights reserved, see COPYRIGHT for full restrictions
// https://github.com/idaholab/moose/blob/master/COPYRIGHT
//
// Licensed under LGPL 2.1, please see LICENSE for details
// https://www.gnu.org/licenses/lgpl-2.1.html

#ifdef MOOSE_MFEM_ENABLED

#pragma once

#include "MFEMMassKernel.h"

/**
 * \f[
 * (k du/dt, v)
 * \f]
 */
class MFEMTimeDerivativeMassKernel : public MFEMMassKernel
{
public:
  static InputParameters validParams();

  MFEMTimeDerivativeMassKernel(const InputParameters & parameters);

  /// Get name of the trial variable (gridfunction) the kernel acts on.
  /// Defaults to the name of the test variable labelling the weak form.
  virtual const VariableName & getTrialVariableName() const override { return _var_dot_name; }

protected:
  /// Name of variable (gridfunction) representing time derivative of variable.
  const VariableName _var_dot_name;
};

#endif

Overview
Input Parameters
Input Files
Child Objects