NSViscStressTensorDerivs< T > Class Template Reference

Class outside the Moose hierarchy that contains common functionality for computing derivatives of the viscous stress tensor. More...

#include <NSViscStressTensorDerivs.h>

Public Member Functions
	NSViscStressTensorDerivs (T &x)
Real	dtau (unsigned k, unsigned ell, unsigned m)
	The primary interface for computing viscous stress tensor derivatives. More...

Private Attributes
T &	_data

Detailed Description

template<class T>
class NSViscStressTensorDerivs< T >

Class outside the Moose hierarchy that contains common functionality for computing derivatives of the viscous stress tensor.

This class is templated so that it can be used by either a Kernel object or a BC object.

Definition at line 21 of file NSViscStressTensorDerivs.h.

Constructor & Destructor Documentation

NSViscStressTensorDerivs()

template<class T>

NSViscStressTensorDerivs< T >::NSViscStressTensorDerivs

(

T &

x

)

Definition at line 39 of file NSViscStressTensorDerivs.h.

                                                           : _data(x)
{
}

Member Function Documentation

dtau()

template<class T >

Real NSViscStressTensorDerivs< T >::dtau	(	unsigned	k,
		unsigned	ell,
		unsigned	m
	)

The primary interface for computing viscous stress tensor derivatives.

Requires access to protected data from the the underlying data. Uses index notation from the notes.

Definition at line 45 of file NSViscStressTensorDerivs.h.

Referenced by NSMomentumViscousFlux::computeQpJacobian(), NSMomentumViscousBC::computeQpJacobian(), NSEnergyViscousFlux::computeQpOffDiagJacobian(), NSMomentumViscousFlux::computeQpOffDiagJacobian(), NSMomentumViscousBC::computeQpOffDiagJacobian(), and NSEnergyViscousBC::computeQpOffDiagJacobian().

{
  // Try to access underlying data.  Since this class is a friend, we can
  // directly access _qp and other protected data.  This only works if the
  // individual variables have the **same names** in all types T which may
  // be used to construct this class.

  //
  // Some error checking on input indices...
  //

  // 0 <= k,ell <= 2
  if (k > 2 || ell > 2)
    mooseError("Error, 0 <= k,ell <= 2 violated!");

  // 0 <= m <= 4
  if (m >= 5)
    mooseError("Error, m <= 4 violated!");

  //
  // Convenience variables
  //

  const Real rho = _data._rho[_data._qp];
  const Real rho2 = rho * rho;
  const Real phij = _data._phi[_data._j][_data._qp];

  const Real mu = _data._dynamic_viscosity[_data._qp];
  const Real nu = mu / rho;

  const RealVectorValue U(
      _data._rho_u[_data._qp], _data._rho_v[_data._qp], _data._rho_w[_data._qp]);

  const Real divU = _data._grad_rho_u[_data._qp](0) + _data._grad_rho_v[_data._qp](1) +
                    _data._grad_rho_w[_data._qp](2);

  // This makes a copy...but the resulting code is cleaner
  std::vector<RealVectorValue> gradU(3);
  gradU[0] = _data._grad_rho_u[_data._qp];
  gradU[1] = _data._grad_rho_v[_data._qp];
  gradU[2] = _data._grad_rho_w[_data._qp];

  // So we can refer to gradients without repeated indexing.
  const RealVectorValue & grad_phij = _data._grad_phi[_data._j][_data._qp];
  const RealVectorValue & grad_rho = _data._grad_rho[_data._qp];

  switch (m)
  {
    case 0: // density
    {
      const Real term1 = 2.0 / rho2 * (U(k) * grad_rho(ell) + U(ell) * grad_rho(k)) * phij;
      const Real term2 = -1.0 / rho *
                         ((gradU[k](ell) + gradU[ell](k)) * phij +
                          (U(k) * grad_phij(ell) + U(ell) * grad_phij(k)));

      // Kronecker delta terms
      Real term3 = 0.0;
      Real term4 = 0.0;
      if (k == ell)
      {
        term3 = -4.0 / 3.0 / rho2 * (U * grad_rho) * phij;
        term4 = 2.0 / 3.0 / rho * (U * grad_phij + divU * phij);
      }

      // Sum up result and return
      return nu * (term1 + term2 + term3 + term4);
    }

    // momentums
    case 1:
    case 2:
    case 3:
    {
      // note: when comparing m to k or ell, or indexing into Points,
      // must map m -> 0, 1, 2 by subtracting 1.
      const unsigned m_local = m - 1;

      // Kronecker delta terms
      const Real delta_km = (k == m_local ? 1.0 : 0.0);
      const Real delta_ellm = (ell == m_local ? 1.0 : 0.0);
      const Real delta_kell = (k == ell ? 1.0 : 0.0);

      return nu *
             (
                 /*     */ delta_km * (grad_phij(ell) - (phij / rho) * grad_rho(ell)) +
                 /*     */ delta_ellm * (grad_phij(k) - (phij / rho) * grad_rho(k)) -
                 (2. / 3.) * delta_kell * (grad_phij(m_local) - (phij / rho) * grad_rho(m_local)));
    } // end case 1,2,3

    case 4:
      // Derivative wrt to energy variable is zero.
      return 0.;

    default:
      mooseError("Invalid variable requested.");
      break;
  }

  return 0.;
}

Member Data Documentation

_data

template<class T>

T& NSViscStressTensorDerivs< T >::_data

private

Definition at line 35 of file NSViscStressTensorDerivs.h.

---

The documentation for this class was generated from the following file:

• navier_stokes/include/userobjects/NSViscStressTensorDerivs.h