LBMSmagorinskyMRTCollision

Template object for LBM collision dynamics

This objects implements commonly used collision dynamics for Lattice Boltzmann simulation. Currently available collision operators are BGK single relaxation time and Multi Relaxation Time (MRT) operators. The additional operation is available to project the non-equilibrium distribution onto Hermite space to achieve stability with the boolean parameter projection. For high Reynolds number simulations, Smagorinsky LES collision dynamics is available for both BGK and MRT operators.

Overview

Template for multiple LBM collision operators:

BGK: single-relaxation time model (LBMBGKCollision).
MRT: multi-relaxation time in moment space (LBMMRTCollision).
Smagorinsky: eddy-viscosity based turbulence (LBMSmagorinskyCollision, LBMSmagorinskyMRTCollision).

Supply incoming and equilibrium distributions via "f" and "feq". Relaxation parameter related to viscous stress is controlled with "tau0"; Smagorinsky constant can be controlled via "Cs".

Example Input File Syntax

[TensorComputes<<<{"href": "../../syntax/TensorComputes/index.html"}>>>]
  [Solve<<<{"href": "../../syntax/TensorComputes/Solve/index.html"}>>>]
    [collision]
      type = LBMBGKCollision<<<{"description": "Template object for LBM collision dynamics", "href": "LBMCollisionDynamics.html"}>>>
      buffer<<<{"description": "The buffer this compute is writing to"}>>> = fpc
      f<<<{"description": "Input buffer distribution function"}>>> = f
      feq<<<{"description": "Input buffer equilibrium distribution function"}>>> = feq
      tau0<<<{"description": "Relaxation parameter"}>>> = 1.0
    []
  []
[]

Input Parameters

bufferThe buffer this compute is writing to
C++ Type:std::string
Controllable:No
Description:The buffer this compute is writing to
fInput buffer distribution function
C++ Type:std::string
Controllable:No
Description:Input buffer distribution function
feqInput buffer equilibrium distribution function
C++ Type:std::string
Controllable:No
Description:Input buffer equilibrium distribution function

Required Parameters

Cs0.1Smagorinsky constant
Default:0.1
C++ Type:std::string
Controllable:No
Description:Smagorinsky constant
is_dynamic_relaxationFalseWhether or not to use dynamic relaxation.
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not to use dynamic relaxation.
local_relaxation_matrixSLocally computed diagonal relaxation matrix
Default:S
C++ Type:std::string
Controllable:No
Description:Locally computed diagonal relaxation matrix
projectionFalseWhether or not to project non-equilibrium onto Hermite space.
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not to project non-equilibrium onto Hermite space.
tau01.0Relaxation parameter
Default:1.0
C++ Type:std::string
Controllable:No
Description:Relaxation parameter
tau_tensortau_tensorRelaxation tensor
Default:tau_tensor
C++ Type:std::string
Controllable:No
Description:Relaxation tensor

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/lbm/smagorinsky_mrt.i)

(test/tests/lbm/channel2D.i)

[Domain]
  dim = 2
  nx = 10
  ny = 10
  mesh_mode = DUMMY
  parallel_mode = REAL_SPACE
  periodic_directions = 'X Y'
[]

[Stencil]
  [d2q9]
    type = LBMD2Q9
  []
[]

[TensorBuffers]
  [f]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [feq]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [fpc]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [velocity]
    type=LBMTensorBuffer
    buffer_type = mv
  []
  [density]
    type=LBMTensorBuffer
    buffer_type = ms
  []
  [speed]
    type=LBMTensorBuffer
    buffer_type = ms
  []
[]

[TensorComputes]
  [Initialize]
    [initial_density]
      type = LBMConstantTensor
      buffer = density
      constants = 1.0
    []
    [initial_velocity]
      type = LBMConstantTensor
      buffer = velocity
      constants = '0.0 0.0'
    []
    [initial_equilibrium]
      type = LBMEquilibrium
      buffer = feq
      bulk = density
      velocity = velocity
    []
    [initial_distribution]
      type = LBMEquilibrium
      buffer = f
      bulk = density
      velocity = velocity
    []
    [initial_distribution_pc]
      type = LBMEquilibrium
      buffer = fpc
      bulk = density
      velocity = velocity
    []
  []
  [Solve]
    [equilibrium]
      type=LBMEquilibrium
      buffer = feq
      bulk = density
      velocity = velocity
    []
    [collision]
      type=LBMBGKCollision
      buffer = fpc
      f = f
      feq = feq
      tau0 = 1.0
    []
    [density]
      type = LBMComputeDensity
      buffer = density
      f = f
    []
    [velocity]
      type = LBMComputeVelocity
      buffer = velocity
      f = f
      rho = density
      add_body_force = true
      body_force_x = 0.0001
    []
    [speed]
      type = LBMComputeVelocityMagnitude
      buffer = speed
      velocity = velocity
    []
    [residual]
      type = LBMComputeResidual
      buffer = speed
      speed = speed
    []
  []
  [Boundary]
    [top]
      type = LBMBounceBack
      buffer = f
      f_old = fpc
      boundary = top
    []
    [bottom]
      type = LBMBounceBack
      buffer = f
      f_old = fpc
      boundary = bottom
    []
  []
[]

[TensorSolver]
  type = LBMStream
  buffer = f
  f_old = fpc
[]

[Problem]
  type = LatticeBoltzmannProblem
  substeps = 10
[]

[Postprocessors]
  [velocity_min]
    type = TensorExtremeValuePostprocessor
    buffer = velocity
    value_type = MIN
  []
  [velocity_max]
    type = TensorExtremeValuePostprocessor
    buffer = velocity
    value_type = MAX
  []
  [speed_min]
    type = TensorExtremeValuePostprocessor
    buffer = speed
    value_type = MIN
  []
  [speed_max]
    type = TensorExtremeValuePostprocessor
    buffer = speed
    value_type = MAX
  []
  [density_min]
    type = TensorExtremeValuePostprocessor
    buffer = density
    value_type = MIN
  []
  [densty_max]
    type = TensorExtremeValuePostprocessor
    buffer = density
    value_type = MAX
  []
[]

[Executioner]
  type = Transient
  num_steps = 11
[]

[Outputs]
  file_base = channel2D
  csv = true
[]

(test/tests/lbm/smagorinsky_mrt.i)

[Domain]
  dim = 2
  nx = 10
  ny = 10
  mesh_mode = DUMMY
  parallel_mode = REAL_SPACE
  periodic_directions = 'X Y'
[]

[Stencil]
  [d2q9]
    type = LBMD2Q9
  []
[]

[TensorBuffers]
  [f]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [feq]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [fpc]
    type = LBMTensorBuffer
    buffer_type = df
  []
  [velocity]
    type=LBMTensorBuffer
    buffer_type = mv
  []
  [density]
    type=LBMTensorBuffer
    buffer_type = ms
  []
  [speed]
    type=LBMTensorBuffer
    buffer_type = ms
  []
[]

[TensorComputes]
  [Initialize]
    [initial_density]
      type = LBMConstantTensor
      buffer = density
      constants = 1.0
    []
    [initial_velocity]
      type = LBMConstantTensor
      buffer = velocity
      constants = '0.0 0.0'
    []
    [initial_equilibrium]
      type = LBMEquilibrium
      buffer = feq
      bulk = density
      velocity = velocity
    []
    [initial_distribution]
      type = LBMEquilibrium
      buffer = f
      bulk = density
      velocity = velocity
    []
    [initial_distribution_pc]
      type = LBMEquilibrium
      buffer = fpc
      bulk = density
      velocity = velocity
    []
  []
  [Solve]
    [root]
      [equilibrium]
        type=LBMEquilibrium
        buffer = feq
        bulk = density
        velocity = velocity
      []
      [collision]
        type=LBMSmagorinskyMRTCollision
        buffer = fpc
        f = f
        feq = feq
        tau0 = 1.0
      []
      [density]
        type = LBMComputeDensity
        buffer = density
        f = f
      []
      [velocity]
        type = LBMComputeVelocity
        buffer = velocity
        f = f
        rho = density
        add_body_force = true
        body_force_x = 0.0001
      []
      [speed]
        type = LBMComputeVelocityMagnitude
        buffer = speed
        velocity = velocity
      []
      [residual]
        type = LBMComputeResidual
        buffer = speed
        speed = speed
      []
    []
  []
  [Boundary]
    [top]
      type = LBMBounceBack
      buffer = f
      f_old = fpc
      boundary = top
    []
    [bottom]
      type = LBMBounceBack
      buffer = f
      f_old = fpc
      boundary = bottom
    []
  []
[]

[TensorSolver]
  type = LBMStream
  buffer = f
  f_old = fpc
  root_compute = root
[]

[Problem]
  type = LatticeBoltzmannProblem
  substeps = 11
[]

[Postprocessors]
  [velocity_min]
    type = TensorExtremeValuePostprocessor
    buffer = velocity
    value_type = MIN
  []
  [velocity_max]
    type = TensorExtremeValuePostprocessor
    buffer = velocity
    value_type = MAX
  []
  [speed_min]
    type = TensorExtremeValuePostprocessor
    buffer = speed
    value_type = MIN
  []
  [speed_max]
    type = TensorExtremeValuePostprocessor
    buffer = speed
    value_type = MAX
  []
  [density_min]
    type = TensorExtremeValuePostprocessor
    buffer = density
    value_type = MIN
  []
  [densty_max]
    type = TensorExtremeValuePostprocessor
    buffer = density
    value_type = MAX
  []
[]

[Executioner]
  type = Transient
  num_steps = 5
[]

[Outputs]
  file_base = smagorinsky_mrt
  csv = true
[]

Overview
Example Input File Syntax
Input Parameters
Input Files