INSFVTurbulentViscosityWallFunction.C

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

#include "INSFVTurbulentViscosityWallFunction.h"
#include "Function.h"
#include "NavierStokesMethods.h"

registerMooseObject("NavierStokesApp", INSFVTurbulentViscosityWallFunction);

InputParameters
INSFVTurbulentViscosityWallFunction::validParams()
{
  InputParameters params = FVDirichletBCBase::validParams();
  params.addClassDescription("Adds Dirichlet BC for wall values of the turbulent viscosity.");
  params.addRequiredParam<MooseFunctorName>("u", "The velocity in the x direction.");
  params.addParam<MooseFunctorName>("v", "The velocity in the y direction.");
  params.addParam<MooseFunctorName>("w", "The velocity in the z direction.");
  params.addRequiredParam<MooseFunctorName>(NS::density, "Density");
  params.addRequiredParam<MooseFunctorName>(NS::mu, "Dynamic viscosity.");
  params.addRequiredParam<MooseFunctorName>(NS::mu_t, "The turbulent viscosity.");
  params.addParam<MooseFunctorName>(NS::TKE, "The turbulent kinetic energy.");
  params.addParam<Real>("C_mu", 0.09, "Coupled turbulent kinetic energy closure.");

  MooseEnum wall_treatment("eq_newton eq_incremental eq_linearized neq", "neq");
  params.addParam<MooseEnum>(
      "wall_treatment", wall_treatment, "The method used for computing the wall functions");
  return params;
}

INSFVTurbulentViscosityWallFunction::INSFVTurbulentViscosityWallFunction(
    const InputParameters & params)
  : FVDirichletBCBase(params),
    _dim(_subproblem.mesh().dimension()),
    _u_var(getFunctor<ADReal>("u")),
    _v_var(params.isParamValid("v") ? &(getFunctor<ADReal>("v")) : nullptr),
    _w_var(params.isParamValid("w") ? &(getFunctor<ADReal>("w")) : nullptr),
    _rho(getFunctor<ADReal>(NS::density)),
    _mu(getFunctor<ADReal>(NS::mu)),
    _mu_t(getFunctor<ADReal>(NS::mu_t)),
    _k(getFunctor<ADReal>(NS::TKE)),
    _C_mu(getParam<Real>("C_mu")),
    _wall_treatment(getParam<MooseEnum>("wall_treatment").getEnum<NS::WallTreatmentEnum>()),
    _preserve_sparsity_pattern(_fv_problem.preserveMatrixSparsityPattern())
{
}

ADReal
INSFVTurbulentViscosityWallFunction::boundaryValue(const FaceInfo & fi,
                                                   const Moose::StateArg & /* state */) const
{
  using std::abs, std::max, std::sqrt, std::pow, std::log;

  // if on an internal face (internal to the mesh, but an external boundary of the flow area),
  // we have to select the element on which the flow variables / viscosity is defined
  const bool use_elem = (fi.faceType(_var_sys_numbers_pair) == FaceInfo::VarFaceNeighbors::ELEM);
  const Real wall_dist = abs(
      ((use_elem ? fi.elemCentroid() : fi.neighborCentroid()) - fi.faceCentroid()) * fi.normal());
  const Elem * const elem_ptr = use_elem ? fi.elemPtr() : fi.neighborPtr();
  const auto elem_arg = makeElemArg(elem_ptr);

  // Get the previous non linear iteration values
  const auto old_state = Moose::StateArg(1, Moose::SolutionIterationType::Nonlinear);
  const auto mu = _mu(elem_arg, old_state);
  const auto rho = _rho(elem_arg, old_state);

  // Get the velocity vector
  ADRealVectorValue velocity(_u_var(elem_arg, old_state));
  if (_v_var)
    velocity(1) = (*_v_var)(elem_arg, old_state);
  if (_w_var)
    velocity(2) = (*_w_var)(elem_arg, old_state);

  // Compute the velocity and direction of the velocity component that is parallel to the wall
  const auto parallel_speed =
      NS::computeSpeed<ADReal>(velocity - velocity * (fi.normal()) * (fi.normal()));

  // Switch for determining the near wall quantities
  // wall_treatment can be: "eq_newton eq_incremental eq_linearized neq"
  ADReal y_plus;
  ADReal mut_log; // turbulent log-layer viscosity
  ADReal mu_wall; // total wall viscosity to obtain the shear stress at the wall

  if (_wall_treatment == NS::WallTreatmentEnum::EQ_NEWTON)
  {
    // Full Newton-Raphson solve to find the wall quantities from the law of the wall
    const auto u_tau = NS::findUStar<ADReal>(mu, rho, parallel_speed, wall_dist);
    y_plus = wall_dist * u_tau * rho / mu;
    mu_wall = rho * Utility::pow<2>(u_tau) * wall_dist / parallel_speed;
    mut_log = mu_wall - mu;
  }
  else if (_wall_treatment == NS::WallTreatmentEnum::EQ_INCREMENTAL)
  {
    // Incremental solve on y_plus to get the near-wall quantities
    y_plus = NS::findyPlus<ADReal>(mu, rho, max(parallel_speed, 1e-10), wall_dist);
    mu_wall =
        mu * (NS::von_karman_constant * y_plus / log(max(NS::E_turb_constant * y_plus, 1 + 1e-4)));
    mut_log = mu_wall - mu;
  }
  else if (_wall_treatment == NS::WallTreatmentEnum::EQ_LINEARIZED)
  {
    // Linearized approximation to the wall function to find the near-wall quantities faster
    const ADReal a_c = 1 / NS::von_karman_constant;
    const ADReal b_c =
        1 / NS::von_karman_constant * (log(NS::E_turb_constant * max(wall_dist, 1.0) / mu) + 1.0);
    const ADReal c_c = parallel_speed;

    const auto u_tau = (-b_c + sqrt(pow(b_c, 2) + 4.0 * a_c * c_c)) / (2.0 * a_c);
    y_plus = wall_dist * u_tau * rho / mu;
    mu_wall = rho * Utility::pow<2>(u_tau) * wall_dist / parallel_speed;
    mut_log = mu_wall - mu;
  }
  else if (_wall_treatment == NS::WallTreatmentEnum::NEQ)
  {
    // Assign non-equilibrium wall function value
    y_plus = pow(_C_mu, 0.25) * wall_dist * sqrt(_k(elem_arg, old_state)) * rho / mu;
    mu_wall = mu * (NS::von_karman_constant * y_plus /
                    log(max(NS::E_turb_constant * y_plus, 1.0 + 1e-4)));
    mut_log = mu_wall - mu;
  }
  else
    mooseAssert(false,
                "For `INSFVTurbulentViscosityWallFunction` , wall treatment should not reach here");

  ADReal residual = 0;
  // To keep the same sparsity pattern for all y_plus
  if (_preserve_sparsity_pattern)
    residual = 0 * mut_log * y_plus;

  if (y_plus <= 5.0)
    // sub-laminar layer
    residual += 0.0;
  else if (y_plus >= 30.0)
    // log-layer
    residual += max(mut_log, NS::mu_t_low_limit);
  else
  {
    // buffer layer
    const auto blending_function = (y_plus - 5.0) / 25.0;
    // the blending depends on the mut_log at y+=30
    const auto mut_log = mu * _mut_30;
    residual += max(blending_function * mut_log, NS::mu_t_low_limit);
  }
  return residual;
}