NSWeakStagnationInletBC

under construction:Undocumented Class

The NSWeakStagnationInletBC has not been documented. The content listed below should be used as a starting point for documenting the class, which includes the typical automatic documentation associated with a MooseObject; however, what is contained is ultimately determined by what is necessary to make the documentation clear for users.


# NSWeakStagnationInletBC

!syntax description /Modules/NavierStokes/BCs/NSWeakStagnationInletBC

## Overview

!! Replace these lines with information regarding the NSWeakStagnationInletBC object.

## Example Input File Syntax

!! Describe and include an example of how to use the NSWeakStagnationInletBC object.

!syntax parameters /Modules/NavierStokes/BCs/NSWeakStagnationInletBC

!syntax inputs /Modules/NavierStokes/BCs/NSWeakStagnationInletBC

!syntax children /Modules/NavierStokes/BCs/NSWeakStagnationInletBC

This class facilitates adding weak stagnation inlet BCs via an Action by setting up the required parameters.

Input Parameters

boundaryThe list of boundary IDs from the mesh where this boundary condition applies
C++ Type:std::vector
Options:
Description:The list of boundary IDs from the mesh where this boundary condition applies
fluid_propertiesThe name of the user object for fluid properties
C++ Type:UserObjectName
Options:
Description:The name of the user object for fluid properties
stagnation_pressureThe specifed stagnation pressure
C++ Type:double
Options:
Description:The specifed stagnation pressure
stagnation_temperatureThe specifed stagnation temperature
C++ Type:double
Options:
Description:The specifed stagnation temperature
sxx-component of specifed flow direction
C++ Type:double
Options:
Description:x-component of specifed flow direction

Required Parameters

sy0y-component of specifed flow direction
Default:0
C++ Type:double
Options:
Description:y-component of specifed flow direction
sz0z-component of specifed flow direction
Default:0
C++ Type:double
Options:
Description:z-component of specifed flow direction

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.

Advanced Parameters

Input Files

modules/navier_stokes/test/tests/step/step.i
modules/navier_stokes/test/tests/bump/bump.i

modules/navier_stokes/test/tests/step/step.i

# Navier-Stokes (or Euler) flow of an ideal gas over a step.
#
# Note: this problem is not currently a regression test for the
# Navier-Stokes module since it is in some sense ill-posed.  As
# discussed in [0], the sharp corner of the step (both forward and
# backward-facing) introduces a singularity in the first derivative of
# the velocity and pressure fields, and therefore produces large
# numerical errors in the neighborhood of these points.  Physically,
# this numerical error can be interpreted as causing an artificial
# "boundary layer" to form just above the step, as well as a spurious
# production of entropy even though the flow remains subsonic.
# Nevertheless, the forward-facing step problem in particular remains
# a challenging and well-document test problem for flow solvers, and
# this input file is included to help facilitate its development and
# employment by users of the module.
#
# [0]: Woodward and Colella, "The numerical simulation of
# two-dimenstional fluid flow with strong shocks," Journal of
# Computational Physics 54(1), pp. 115-173, 1984

[Mesh]
  type = FileMesh
  file = step.e
  dim = 2
  # uniform_refine = 3
[]


[Modules]
  [./FluidProperties]
    [./ideal_gas]
      type = IdealGasFluidProperties
      gamma = 1.4
      R = 287
    [../]
  [../]

  [./NavierStokes]
    [./Variables]
      #         'rho rhou rhov   rhoE'
      scaling = '1.  1.    1.    9.869232667160121e-6'
      family = LAGRANGE
      order = FIRST
    [../]

    [./ICs]
      initial_pressure = 101325.
      initial_temperature = 300.
      initial_velocity = '173.594354746921 0 0' # Mach 0.5: = 0.5*sqrt(gamma*R*T)
      fluid_properties = ideal_gas
    [../]

    [./Kernels]
      fluid_properties = ideal_gas
    [../]

    [./BCs]
      [./inlet]
        type = NSWeakStagnationInletBC
        boundary = 'left'
        stagnation_pressure = 120192.995549849 # Pa, Mach=0.5 at 1 atm
        stagnation_temperature = 315 # K, Mach=0.5 at 1 atm
        sx = 1.
        sy = 0.
        fluid_properties = ideal_gas
      [../]

      [./solid_walls]
        type = NSNoPenetrationBC
        boundary = 'top bottom step_top step_left step_right'
        fluid_properties = ideal_gas
      [../]

      [./outlet]
        type = NSStaticPressureOutletBC
        boundary = 'right'
        specified_pressure = 101325 # Pa
        fluid_properties = ideal_gas
      [../]
    [../]
  [../]
[]



[Materials]
  [./fluid]
    type = Air
    block = 1
    rho = rho
    rhou = rhou
    rhov = rhov
    rhoE = rhoE
    vel_x = vel_x
    vel_y = vel_y
    temperature = temperature
    enthalpy = enthalpy
    # This value is not used in the Euler equations, but it *is* used
    # by the stabilization parameter computation, which it decreases
    # the amount of artificial viscosity added, so it's best to use a
    # realistic value.
    dynamic_viscosity = 0.0
    fluid_properties = ideal_gas
  [../]
[]



[Preconditioning]
  [./SMP_PJFNK]
    type = SMP
    full = true
    solve_type = 'PJFNK'
  [../]
[]



[Executioner]
  type = Transient
  dt = 5.e-5
  dtmin = 1.e-5
  start_time = 0.0
  num_steps = 10000
  nl_rel_tol = 1e-5
  nl_abs_tol = 1e-9
  # nl_abs_step_tol = 1e-15
  nl_max_its = 5
  l_tol = 1e-4 # Relative linear tolerance for each Krylov solve
  l_max_its = 100 # Number of linear iterations for each Krylov solve

  # Specify the order as FIRST, otherwise you will get warnings in DEBUG mode...
  [./Quadrature]
    type = TRAP
    order = FIRST
  [../]
[]



[Outputs]
  file_base = step_out
  interval = 1
  exodus = true
[]

modules/navier_stokes/test/tests/bump/bump.i

# Euler flow of an ideal gas over a Gaussian "bump".
#
# The inlet is a stagnation pressure and temperature BC which
# corresponds to subsonic (M=0.5) flow with a static pressure of 1 atm
# and static temperature of 300K.  The outlet consists of a
# weakly-imposed static pressure BC of 1 atm.  The top and bottom
# walls of the channel weakly impose the "no normal flow" BC. The
# problem is initialized with freestream flow throughout the domain.
# Although this initial condition is less physically realistic, it
# helps the problem reach steady state more quickly.
#
# There is a sequence of uniformly-refined, geometry-fitted meshes
# from Yidong Xia available for solving this classical subsonic test
# problem (see the Mesh block below).  A coarse grid is used for the
# actual regression test, but changing one line in the Mesh block is
# sufficient to run this problem with different meshes.  An
# entropy-based error estimate is also provided, and can be used to
# demonstrate convergence of the numerical solution (since the true
# solution should produce zero entropy).  The error should converge at
# second-order in this norm.
[Mesh]
  # Bi-Linear elements
  # file = SmoothBump_quad_ref1_Q1.msh # 84 elems, 65 nodes
  # file = SmoothBump_quad_ref2_Q1.msh # 192 elems, 225 nodes
  # file = SmoothBump_quad_ref3_Q1.msh # 768 elems, 833 nodes
  # file = SmoothBump_quad_ref4_Q1.msh # 3072 elems, 3201 nodes
  # file = SmoothBump_quad_ref5_Q1.msh # 12288 elems, 12545 nodes
  # Bi-Quadratic elements
  # file = SmoothBump_quad_ref0_Q2.msh # 32 elems, 65 nodes
  # file = SmoothBump_quad_ref1_Q2.msh # 84 elems, 225 nodes
  file = SmoothBump_quad_ref2_Q2.msh # 260 elems, 833 nodes
  # file = SmoothBump_quad_ref3_Q2.msh # 900 elems, 3201 nodes
  # file = SmoothBump_quad_ref4_Q2.msh # 3332 elems, 12545 nodes
  # file = SmoothBump_quad_ref5_Q2.msh # 12804 elems, 49665 nodes
[]



[Modules]
  [./FluidProperties]
    [./ideal_gas]
      type = IdealGasFluidProperties
      gamma = 1.4
      molar_mass = 0.02897024320557491
    [../]
  [../]

  [./NavierStokes]
    [./Variables]
      #         'rho rhou rhov   rhoE'
      scaling = '1.  1.    1.    9.869232667160121e-6'
      family = LAGRANGE
      order = FIRST
    [../]

    [./ICs]
      initial_pressure = 101325.
      initial_temperature = 300.
      initial_velocity = '173.594354746921 0 0' # Mach 0.5: = 0.5*sqrt(gamma*R*T)
      fluid_properties = ideal_gas
    [../]

    [./Kernels]
      fluid_properties = ideal_gas
    [../]

    [./BCs]
      [./inlet]
        type = NSWeakStagnationInletBC
        boundary = '1'
        stagnation_pressure = 120192.995549849 # Pa, Mach=0.5 at 1 atm
        stagnation_temperature = 315 # K, Mach=0.5 at 1 atm
        sx = 1.
        sy = 0.
        fluid_properties = ideal_gas
      [../]

      [./solid_walls]
        type = NSNoPenetrationBC
        boundary = '3 4' # 'Lower Wall, Upper Wall'
        fluid_properties = ideal_gas
      [../]

      [./outlet]
        type = NSStaticPressureOutletBC
        boundary = '2' # 'Outflow'
        specified_pressure = 101325 # Pa
        fluid_properties = ideal_gas
      [../]
    [../]
  [../]
[]



[Materials]
  [./fluid]
    type = Air
    block = 0 # 'MeshInterior'
    rho = rho
    rhou = rhou
    rhov = rhov
    rhoE = rhoE
    vel_x = vel_x
    vel_y = vel_y
    temperature = temperature
    enthalpy = enthalpy
    # This value is not used in the Euler equations, but it *is* used
    # by the stabilization parameter computation, which it decreases
    # the amount of artificial viscosity added, so it's best to use a
    # realistic value.
    dynamic_viscosity = 0.0
    fluid_properties = ideal_gas
  [../]
[]



[Postprocessors]
  [./entropy_error]
    type = NSEntropyError
    execute_on = 'initial timestep_end'
    block = 0
    rho_infty = 1.1768292682926829
    p_infty = 101325
    rho = rho
    pressure = pressure
    fluid_properties = ideal_gas
  [../]
[]



[Preconditioning]
  [./SMP_PJFNK]
    type = SMP
    full = true
    solve_type = 'PJFNK'
  [../]
[]



[Executioner]
  type = Transient
  dt = 5.e-5
  dtmin = 1.e-5
  start_time = 0.0
  num_steps = 10
  nl_rel_tol = 1e-9
  nl_max_its = 5
  l_tol = 1e-4
  l_max_its = 100

  # We use trapezoidal quadrature.  This improves stability by
  # mimicking the "group variable" discretization approach.
  [./Quadrature]
    type = TRAP
    order = FIRST
  [../]
[]



[Outputs]
  interval = 1
  exodus = true
[]

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