コード例 #1
0
  void LowMachNavierStokes<Mu,SH,TC>::assemble_mass_time_deriv( bool /*compute_jacobian*/, 
								AssemblyContext& context,
								CachedValues& cache )
  {
    // The number of local degrees of freedom in each variable.
    const unsigned int n_p_dofs = context.get_dof_indices(this->_p_var).size();

    // Element Jacobian * quadrature weights for interior integration.
    const std::vector<libMesh::Real> &JxW =
      context.get_element_fe(this->_u_var)->get_JxW();

    // The pressure shape functions at interior quadrature points.
    const std::vector<std::vector<libMesh::Real> >& p_phi =
      context.get_element_fe(this->_p_var)->get_phi();

    libMesh::DenseSubVector<libMesh::Number> &Fp = context.get_elem_residual(this->_p_var); // R_{p}

    unsigned int n_qpoints = context.get_element_qrule().n_points();

    for (unsigned int qp=0; qp != n_qpoints; qp++)
      {
	libMesh::Number u, v, T;
	u = cache.get_cached_values(Cache::X_VELOCITY)[qp];
	v = cache.get_cached_values(Cache::Y_VELOCITY)[qp];

	T = cache.get_cached_values(Cache::TEMPERATURE)[qp];

	libMesh::Gradient grad_u = cache.get_cached_gradient_values(Cache::X_VELOCITY_GRAD)[qp];
	libMesh::Gradient grad_v = cache.get_cached_gradient_values(Cache::Y_VELOCITY_GRAD)[qp];

	libMesh::Gradient grad_T = cache.get_cached_gradient_values(Cache::TEMPERATURE_GRAD)[qp];

	libMesh::NumberVectorValue U(u,v);
	if (this->_dim == 3)
	  U(2) = cache.get_cached_values(Cache::Z_VELOCITY)[qp]; // w

	libMesh::Number divU = grad_u(0) + grad_v(1);
	if (this->_dim == 3)
          {
	    libMesh::Gradient grad_w = cache.get_cached_gradient_values(Cache::Z_VELOCITY_GRAD)[qp];
	    divU += grad_w(2);
          }

	// Now a loop over the pressure degrees of freedom.  This
	// computes the contributions of the continuity equation.
	for (unsigned int i=0; i != n_p_dofs; i++)
	  {
	    Fp(i) += (-U*grad_T/T + divU)*p_phi[i][qp]*JxW[qp];
	  }
      }

    return;
  }
コード例 #2
0
  void LowMachNavierStokes<Mu,SH,TC>::assemble_thermo_press_elem_time_deriv( bool /*compute_jacobian*/,
									     AssemblyContext& context )
  {
    // Element Jacobian * quadrature weights for interior integration
    const std::vector<libMesh::Real> &JxW = 
      context.get_element_fe(this->_T_var)->get_JxW();

    // The number of local degrees of freedom in each variable
    const unsigned int n_p0_dofs = context.get_dof_indices(this->_p0_var).size();

    // The subvectors and submatrices we need to fill:
    libMesh::DenseSubVector<libMesh::Real> &F_p0 = context.get_elem_residual(this->_p0_var);

    unsigned int n_qpoints = context.get_element_qrule().n_points();

    for (unsigned int qp = 0; qp != n_qpoints; ++qp)
      {
	libMesh::Number T;
	T = context.interior_value(this->_T_var, qp);

	libMesh::Gradient grad_u, grad_v, grad_w;
	grad_u = context.interior_gradient(this->_u_var, qp);
	grad_v = context.interior_gradient(this->_v_var, qp);
	if (this->_dim == 3)
	  grad_w = context.interior_gradient(this->_w_var, qp);

	libMesh::Number divU = grad_u(0) + grad_v(1);
	if(this->_dim==3)
	  divU += grad_w(2);

	//libMesh::Number cp = this->_cp(T);
	//libMesh::Number cv = cp + this->_R;
	//libMesh::Number gamma = cp/cv;
	//libMesh::Number gamma_ratio = gamma/(gamma-1.0);

	libMesh::Number p0 = context.interior_value( this->_p0_var, qp );

	for (unsigned int i = 0; i != n_p0_dofs; ++i)
	  {
	    F_p0(i) += (p0/T - this->_p0/this->_T0)*JxW[qp];
	    //F_p0(i) -= p0*gamma_ratio*divU*JxW[qp];
	  } // End DoF loop i
      }

    return;
  }
コード例 #3
0
  void ElasticCableRayleighDamping<StressStrainLaw>::damping_residual( bool compute_jacobian,
                                                                       AssemblyContext& context,
                                                                       CachedValues& /*cache*/)
  {
    // First, do the "mass" contribution
    this->mass_residual_impl(compute_jacobian,
                               context,
                               &libMesh::FEMContext::interior_rate,
                               &libMesh::DiffContext::get_elem_solution_rate_derivative,
                               _mu_factor);

    // Now do the stiffness contribution
    const unsigned int n_u_dofs = context.get_dof_indices(this->_disp_vars.u()).size();

    const std::vector<libMesh::Real> &JxW =
      this->get_fe(context)->get_JxW();

    // Residuals that we're populating
    libMesh::DenseSubVector<libMesh::Number> &Fu = context.get_elem_residual(this->_disp_vars.u());
    libMesh::DenseSubVector<libMesh::Number> &Fv = context.get_elem_residual(this->_disp_vars.v());
    libMesh::DenseSubVector<libMesh::Number> &Fw = context.get_elem_residual(this->_disp_vars.w());

    //Grab the Jacobian matrix as submatrices
    //libMesh::DenseMatrix<libMesh::Number> &K = context.get_elem_jacobian();
    libMesh::DenseSubMatrix<libMesh::Number> &Kuu = context.get_elem_jacobian(this->_disp_vars.u(),this->_disp_vars.u());
    libMesh::DenseSubMatrix<libMesh::Number> &Kuv = context.get_elem_jacobian(this->_disp_vars.u(),this->_disp_vars.v());
    libMesh::DenseSubMatrix<libMesh::Number> &Kuw = context.get_elem_jacobian(this->_disp_vars.u(),this->_disp_vars.w());
    libMesh::DenseSubMatrix<libMesh::Number> &Kvu = context.get_elem_jacobian(this->_disp_vars.v(),this->_disp_vars.u());
    libMesh::DenseSubMatrix<libMesh::Number> &Kvv = context.get_elem_jacobian(this->_disp_vars.v(),this->_disp_vars.v());
    libMesh::DenseSubMatrix<libMesh::Number> &Kvw = context.get_elem_jacobian(this->_disp_vars.v(),this->_disp_vars.w());
    libMesh::DenseSubMatrix<libMesh::Number> &Kwu = context.get_elem_jacobian(this->_disp_vars.w(),this->_disp_vars.u());
    libMesh::DenseSubMatrix<libMesh::Number> &Kwv = context.get_elem_jacobian(this->_disp_vars.w(),this->_disp_vars.v());
    libMesh::DenseSubMatrix<libMesh::Number> &Kww = context.get_elem_jacobian(this->_disp_vars.w(),this->_disp_vars.w());

    unsigned int n_qpoints = context.get_element_qrule().n_points();

    // All shape function gradients are w.r.t. master element coordinates
    const std::vector<std::vector<libMesh::Real> >& dphi_dxi = this->get_fe(context)->get_dphidxi();

    const libMesh::DenseSubVector<libMesh::Number>& u_coeffs = context.get_elem_solution( this->_disp_vars.u() );
    const libMesh::DenseSubVector<libMesh::Number>& v_coeffs = context.get_elem_solution( this->_disp_vars.v() );
    const libMesh::DenseSubVector<libMesh::Number>& w_coeffs = context.get_elem_solution( this->_disp_vars.w() );

    const libMesh::DenseSubVector<libMesh::Number>& dudt_coeffs = context.get_elem_solution_rate( this->_disp_vars.u() );
    const libMesh::DenseSubVector<libMesh::Number>& dvdt_coeffs = context.get_elem_solution_rate( this->_disp_vars.v() );
    const libMesh::DenseSubVector<libMesh::Number>& dwdt_coeffs = context.get_elem_solution_rate( this->_disp_vars.w() );

    // Need these to build up the covariant and contravariant metric tensors
    const std::vector<libMesh::RealGradient>& dxdxi  = this->get_fe(context)->get_dxyzdxi();

    const unsigned int dim = 1; // The cable dimension is always 1 for this physics

    for (unsigned int qp=0; qp != n_qpoints; qp++)
      {
        // Gradients are w.r.t. master element coordinates
        libMesh::Gradient grad_u, grad_v, grad_w;
        libMesh::Gradient dgradu_dt, dgradv_dt, dgradw_dt;

        for( unsigned int d = 0; d < n_u_dofs; d++ )
          {
            libMesh::RealGradient u_gradphi( dphi_dxi[d][qp] );
            grad_u += u_coeffs(d)*u_gradphi;
            grad_v += v_coeffs(d)*u_gradphi;
            grad_w += w_coeffs(d)*u_gradphi;

            dgradu_dt += dudt_coeffs(d)*u_gradphi;
            dgradv_dt += dvdt_coeffs(d)*u_gradphi;
            dgradw_dt += dwdt_coeffs(d)*u_gradphi;
          }

        libMesh::RealGradient grad_x( dxdxi[qp](0) );
        libMesh::RealGradient grad_y( dxdxi[qp](1) );
        libMesh::RealGradient grad_z( dxdxi[qp](2) );

        libMesh::TensorValue<libMesh::Real> a_cov, a_contra, A_cov, A_contra;
        libMesh::Real lambda_sq = 0;

        this->compute_metric_tensors( qp, *(this->get_fe(context)), context,
                                      grad_u, grad_v, grad_w,
                                      a_cov, a_contra, A_cov, A_contra,
                                      lambda_sq );

        // Compute stress tensor
        libMesh::TensorValue<libMesh::Real> tau;
        ElasticityTensor C;
        this->_stress_strain_law.compute_stress_and_elasticity(dim,a_contra,a_cov,A_contra,A_cov,tau,C);

        libMesh::Real jac = JxW[qp];

        for (unsigned int i=0; i != n_u_dofs; i++)
          {
            libMesh::RealGradient u_gradphi( dphi_dxi[i][qp] );

            libMesh::Real u_diag_factor = _lambda_factor*this->_A*jac*tau(0,0)*dgradu_dt(0)*u_gradphi(0);
            libMesh::Real v_diag_factor = _lambda_factor*this->_A*jac*tau(0,0)*dgradv_dt(0)*u_gradphi(0);
            libMesh::Real w_diag_factor = _lambda_factor*this->_A*jac*tau(0,0)*dgradw_dt(0)*u_gradphi(0);

            const libMesh::Real C1 = _lambda_factor*this->_A*jac*C(0,0,0,0)*u_gradphi(0);

            const libMesh::Real gamma_u = (grad_x(0)+grad_u(0));
            const libMesh::Real gamma_v = (grad_y(0)+grad_v(0));
            const libMesh::Real gamma_w = (grad_z(0)+grad_w(0));

            const libMesh::Real x_term = C1*gamma_u;
            const libMesh::Real y_term = C1*gamma_v;
            const libMesh::Real z_term = C1*gamma_w;

            const libMesh::Real dt_term = dgradu_dt(0)*gamma_u + dgradv_dt(0)*gamma_v + dgradw_dt(0)*gamma_w;

            Fu(i) += u_diag_factor + x_term*dt_term;
            Fv(i) += v_diag_factor + y_term*dt_term;
            Fw(i) += w_diag_factor + z_term*dt_term;
          }

        if( compute_jacobian )
          {
            for(unsigned int i=0; i != n_u_dofs; i++)
              {
                libMesh::RealGradient u_gradphi_I( dphi_dxi[i][qp] );

                for(unsigned int j=0; j != n_u_dofs; j++)
                  {
                    libMesh::RealGradient u_gradphi_J( dphi_dxi[j][qp] );

                    libMesh::Real common_factor = _lambda_factor*this->_A*jac*u_gradphi_I(0);

                    const libMesh::Real diag_term_1 = common_factor*tau(0,0)*u_gradphi_J(0)*context.get_elem_solution_rate_derivative();

                    const libMesh::Real dgamma_du = ( u_gradphi_J(0)*(grad_x(0)+grad_u(0)) );

                    const libMesh::Real dgamma_dv = ( u_gradphi_J(0)*(grad_y(0)+grad_v(0)) );

                    const libMesh::Real dgamma_dw = ( u_gradphi_J(0)*(grad_z(0)+grad_w(0)) );

                    const libMesh::Real diag_term_2_factor = common_factor*C(0,0,0,0)*context.get_elem_solution_derivative();

                    Kuu(i,j) += diag_term_1 + dgradu_dt(0)*diag_term_2_factor*dgamma_du;
                    Kuv(i,j) += dgradu_dt(0)*diag_term_2_factor*dgamma_dv;
                    Kuw(i,j) += dgradu_dt(0)*diag_term_2_factor*dgamma_dw;

                    Kvu(i,j) += dgradv_dt(0)*diag_term_2_factor*dgamma_du;
                    Kvv(i,j) += diag_term_1 + dgradv_dt(0)*diag_term_2_factor*dgamma_dv;
                    Kvw(i,j) += dgradv_dt(0)*diag_term_2_factor*dgamma_dw;

                    Kwu(i,j) += dgradw_dt(0)*diag_term_2_factor*dgamma_du;
                    Kwv(i,j) += dgradw_dt(0)*diag_term_2_factor*dgamma_dv;
                    Kww(i,j) += diag_term_1 + dgradw_dt(0)*diag_term_2_factor*dgamma_dw;

                    const libMesh::Real C1 = common_factor*C(0,0,0,0);

                    const libMesh::Real gamma_u = (grad_x(0)+grad_u(0));
                    const libMesh::Real gamma_v = (grad_y(0)+grad_v(0));
                    const libMesh::Real gamma_w = (grad_z(0)+grad_w(0));

                    const libMesh::Real x_term = C1*gamma_u;
                    const libMesh::Real y_term = C1*gamma_v;
                    const libMesh::Real z_term = C1*gamma_w;

                    const libMesh::Real ddtterm_du = u_gradphi_J(0)*(gamma_u*context.get_elem_solution_rate_derivative()
                                                                     + dgradu_dt(0)*context.get_elem_solution_derivative());

                    const libMesh::Real ddtterm_dv = u_gradphi_J(0)*(gamma_v*context.get_elem_solution_rate_derivative()
                                                                     + dgradv_dt(0)*context.get_elem_solution_derivative());

                    const libMesh::Real ddtterm_dw = u_gradphi_J(0)*(gamma_w*context.get_elem_solution_rate_derivative()
                                                                     + dgradw_dt(0)*context.get_elem_solution_derivative());

                    Kuu(i,j) += x_term*ddtterm_du;
                    Kuv(i,j) += x_term*ddtterm_dv;
                    Kuw(i,j) += x_term*ddtterm_dw;

                    Kvu(i,j) += y_term*ddtterm_du;
                    Kvv(i,j) += y_term*ddtterm_dv;
                    Kvw(i,j) += y_term*ddtterm_dw;

                    Kwu(i,j) += z_term*ddtterm_du;
                    Kwv(i,j) += z_term*ddtterm_dv;
                    Kww(i,j) += z_term*ddtterm_dw;

                    const libMesh::Real dt_term = dgradu_dt(0)*gamma_u + dgradv_dt(0)*gamma_v + dgradw_dt(0)*gamma_w;

                    // Here, we're missing derivatives of C(0,0,0,0) w.r.t. strain
                    // Nonzero for hyperelasticity models
                    const libMesh::Real dxterm_du = C1*u_gradphi_J(0)*context.get_elem_solution_derivative();
                    const libMesh::Real dyterm_dv = dxterm_du;
                    const libMesh::Real dzterm_dw = dxterm_du;

                    Kuu(i,j) += dxterm_du*dt_term;
                    Kvv(i,j) += dyterm_dv*dt_term;
                    Kww(i,j) += dzterm_dw*dt_term;

                  } // end j-loop
              } // end i-loop
          } // end if(compute_jacobian)
      } // end qp loop
  }
コード例 #4
0
  void LowMachNavierStokes<Mu,SH,TC>::assemble_momentum_time_deriv( bool /*compute_jacobian*/, 
								    AssemblyContext& context,
								    CachedValues& cache )
  {
    // The number of local degrees of freedom in each variable.
    const unsigned int n_u_dofs = context.get_dof_indices(this->_u_var).size();

    // Check number of dofs is same for _u_var, v_var and w_var.
    libmesh_assert (n_u_dofs == context.get_dof_indices(this->_v_var).size());
    if (this->_dim == 3)
      libmesh_assert (n_u_dofs == context.get_dof_indices(this->_w_var).size());

    // Element Jacobian * quadrature weights for interior integration.
    const std::vector<libMesh::Real> &JxW =
      context.get_element_fe(this->_u_var)->get_JxW();

    // The pressure shape functions at interior quadrature points.
    const std::vector<std::vector<libMesh::Real> >& u_phi =
      context.get_element_fe(this->_u_var)->get_phi();

    // The velocity shape function gradients at interior quadrature points.
    const std::vector<std::vector<libMesh::RealGradient> >& u_gradphi =
      context.get_element_fe(this->_u_var)->get_dphi();

    libMesh::DenseSubVector<libMesh::Number> &Fu = context.get_elem_residual(this->_u_var); // R_{u}
    libMesh::DenseSubVector<libMesh::Number> &Fv = context.get_elem_residual(this->_v_var); // R_{v}
    libMesh::DenseSubVector<libMesh::Number> &Fw = context.get_elem_residual(this->_w_var); // R_{w}

    unsigned int n_qpoints = context.get_element_qrule().n_points();
    for (unsigned int qp=0; qp != n_qpoints; qp++)
      {
	libMesh::Number u, v, p, p0, T;
	u = cache.get_cached_values(Cache::X_VELOCITY)[qp];
	v = cache.get_cached_values(Cache::Y_VELOCITY)[qp];

	T = cache.get_cached_values(Cache::TEMPERATURE)[qp];
	p = cache.get_cached_values(Cache::PRESSURE)[qp];
	p0 = cache.get_cached_values(Cache::THERMO_PRESSURE)[qp];

	libMesh::Gradient grad_u = cache.get_cached_gradient_values(Cache::X_VELOCITY_GRAD)[qp];
	libMesh::Gradient grad_v = cache.get_cached_gradient_values(Cache::Y_VELOCITY_GRAD)[qp];

	libMesh::Gradient grad_w;
	if (this->_dim == 3)
	  grad_w = cache.get_cached_gradient_values(Cache::Z_VELOCITY_GRAD)[qp];

	libMesh::NumberVectorValue grad_uT( grad_u(0), grad_v(0) ); 
	libMesh::NumberVectorValue grad_vT( grad_u(1), grad_v(1) );
	libMesh::NumberVectorValue grad_wT;
	if( this->_dim == 3 )
	  {
	    grad_uT(2) = grad_w(0);
	    grad_vT(2) = grad_w(1);
	    grad_wT = libMesh::NumberVectorValue( grad_u(2), grad_v(2), grad_w(2) );
	  }

	libMesh::NumberVectorValue U(u,v);
	if (this->_dim == 3)
	  U(2) = cache.get_cached_values(Cache::Z_VELOCITY)[qp]; // w

	libMesh::Number divU = grad_u(0) + grad_v(1);
	if (this->_dim == 3)
	  divU += grad_w(2);

	libMesh::Number rho = this->rho( T, p0 );
      
	// Now a loop over the pressure degrees of freedom.  This
	// computes the contributions of the continuity equation.
	for (unsigned int i=0; i != n_u_dofs; i++)
	  {
	    Fu(i) += ( -rho*U*grad_u*u_phi[i][qp]                 // convection term
		       + p*u_gradphi[i][qp](0)                           // pressure term
		       - this->_mu(T)*(u_gradphi[i][qp]*grad_u + u_gradphi[i][qp]*grad_uT
				       - 2.0/3.0*divU*u_gradphi[i][qp](0) )    // diffusion term
		       + rho*this->_g(0)*u_phi[i][qp]                 // hydrostatic term
		       )*JxW[qp]; 

	    Fv(i) += ( -rho*U*grad_v*u_phi[i][qp]                 // convection term
		       + p*u_gradphi[i][qp](1)                           // pressure term
		       - this->_mu(T)*(u_gradphi[i][qp]*grad_v + u_gradphi[i][qp]*grad_vT
				       - 2.0/3.0*divU*u_gradphi[i][qp](1) )    // diffusion term
		       + rho*this->_g(1)*u_phi[i][qp]                 // hydrostatic term
		       )*JxW[qp];
	    if (this->_dim == 3)
	      {
		Fw(i) += ( -rho*U*grad_w*u_phi[i][qp]                 // convection term
			   + p*u_gradphi[i][qp](2)                           // pressure term
			   - this->_mu(T)*(u_gradphi[i][qp]*grad_w + u_gradphi[i][qp]*grad_wT
					   - 2.0/3.0*divU*u_gradphi[i][qp](2) )    // diffusion term
			   + rho*this->_g(2)*u_phi[i][qp]                 // hydrostatic term
			   )*JxW[qp];
	      }

	    /*
	      if (compute_jacobian && context.get_elem_solution_derivative())
	      {
              libmesh_assert (context.get_elem_solution_derivative() == 1.0);

              for (unsigned int j=0; j != n_u_dofs; j++)
	      {
	      // TODO: precompute some terms like:
	      //   (Uvec*vel_gblgradphivec[j][qp]),
	      //   vel_phi[i][qp]*vel_phi[j][qp],
	      //   (vel_gblgradphivec[i][qp]*vel_gblgradphivec[j][qp])

	      Kuu(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*(Uvec*vel_gblgradphivec[j][qp])       // convection term
	      -_rho*vel_phi[i][qp]*graduvec_x*vel_phi[j][qp]             // convection term
	      -_mu*(vel_gblgradphivec[i][qp]*vel_gblgradphivec[j][qp])); // diffusion term
	      Kuv(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*graduvec_y*vel_phi[j][qp]);           // convection term

	      Kvv(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*(Uvec*vel_gblgradphivec[j][qp])       // convection term
	      -_rho*vel_phi[i][qp]*gradvvec_y*vel_phi[j][qp]             // convection term
	      -_mu*(vel_gblgradphivec[i][qp]*vel_gblgradphivec[j][qp])); // diffusion term
	      Kvu(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*gradvvec_x*vel_phi[j][qp]);           // convection term

	      if (_dim == 3)
	      {
	      Kuw(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*graduvec_z*vel_phi[j][qp]);           // convection term

	      Kvw(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*gradvvec_z*vel_phi[j][qp]);           // convection term

	      Kww(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*(Uvec*vel_gblgradphivec[j][qp])       // convection term
	      -_rho*vel_phi[i][qp]*gradwvec_z*vel_phi[j][qp]             // convection term
	      -_mu*(vel_gblgradphivec[i][qp]*vel_gblgradphivec[j][qp])); // diffusion term
	      Kwu(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*gradwvec_x*vel_phi[j][qp]);           // convection term
	      Kwv(i,j) += JxW[qp] *
	      (-_rho*vel_phi[i][qp]*gradwvec_y*vel_phi[j][qp]);           // convection term
	      }
	      } // end of the inner dof (j) loop

              // Matrix contributions for the up, vp and wp couplings
              for (unsigned int j=0; j != n_p_dofs; j++)
	      {
	      Kup(i,j) += JxW[qp]*vel_gblgradphivec[i][qp](0)*p_phi[j][qp];
	      Kvp(i,j) += JxW[qp]*vel_gblgradphivec[i][qp](1)*p_phi[j][qp];
	      if (_dim == 3)
	      Kwp(i,j) += JxW[qp]*vel_gblgradphivec[i][qp](2)*p_phi[j][qp];
	      } // end of the inner dof (j) loop

	      } // end - if (compute_jacobian && context.get_elem_solution_derivative())

	      } // end of the outer dof (i) loop
	      } // end of the quadrature point (qp) loop
	    */
	  } // End of DoF loop i
      } // End quadrature loop qp

    return;
  }
コード例 #5
0
  void ElasticMembranePressure<PressureType>::element_time_derivative
  ( bool compute_jacobian, AssemblyContext & context )
  {
    unsigned int u_var = this->_disp_vars.u();
    unsigned int v_var = this->_disp_vars.v();
    unsigned int w_var = this->_disp_vars.w();

    const unsigned int n_u_dofs = context.get_dof_indices(u_var).size();

    const std::vector<libMesh::Real> &JxW =
      this->get_fe(context)->get_JxW();

    const std::vector<std::vector<libMesh::Real> >& u_phi =
      this->get_fe(context)->get_phi();

    const MultiphysicsSystem & system = context.get_multiphysics_system();

    unsigned int u_dot_var = system.get_second_order_dot_var(u_var);
    unsigned int v_dot_var = system.get_second_order_dot_var(v_var);
    unsigned int w_dot_var = system.get_second_order_dot_var(w_var);

    libMesh::DenseSubVector<libMesh::Number> &Fu = context.get_elem_residual(u_dot_var);
    libMesh::DenseSubVector<libMesh::Number> &Fv = context.get_elem_residual(v_dot_var);
    libMesh::DenseSubVector<libMesh::Number> &Fw = context.get_elem_residual(w_dot_var);

    libMesh::DenseSubMatrix<libMesh::Number>& Kuv = context.get_elem_jacobian(u_dot_var,v_var);
    libMesh::DenseSubMatrix<libMesh::Number>& Kuw = context.get_elem_jacobian(u_dot_var,w_var);

    libMesh::DenseSubMatrix<libMesh::Number>& Kvu = context.get_elem_jacobian(v_dot_var,u_var);
    libMesh::DenseSubMatrix<libMesh::Number>& Kvw = context.get_elem_jacobian(v_dot_var,w_var);

    libMesh::DenseSubMatrix<libMesh::Number>& Kwu = context.get_elem_jacobian(w_dot_var,u_var);
    libMesh::DenseSubMatrix<libMesh::Number>& Kwv = context.get_elem_jacobian(w_dot_var,v_var);

    unsigned int n_qpoints = context.get_element_qrule().n_points();

    // All shape function gradients are w.r.t. master element coordinates
    const std::vector<std::vector<libMesh::Real> >& dphi_dxi =
      this->get_fe(context)->get_dphidxi();

    const std::vector<std::vector<libMesh::Real> >& dphi_deta =
      this->get_fe(context)->get_dphideta();

    const libMesh::DenseSubVector<libMesh::Number>& u_coeffs = context.get_elem_solution( u_var );
    const libMesh::DenseSubVector<libMesh::Number>& v_coeffs = context.get_elem_solution( v_var );
    const libMesh::DenseSubVector<libMesh::Number>& w_coeffs = context.get_elem_solution( w_var );

    const std::vector<libMesh::RealGradient>& dxdxi  = this->get_fe(context)->get_dxyzdxi();
    const std::vector<libMesh::RealGradient>& dxdeta = this->get_fe(context)->get_dxyzdeta();

    for (unsigned int qp=0; qp != n_qpoints; qp++)
      {
        // sqrt(det(a_cov)), a_cov being the covariant metric tensor of undeformed body
        libMesh::Real sqrt_a = sqrt( dxdxi[qp]*dxdxi[qp]*dxdeta[qp]*dxdeta[qp]
                                     - dxdxi[qp]*dxdeta[qp]*dxdeta[qp]*dxdxi[qp] );

        // Gradients are w.r.t. master element coordinates
        libMesh::Gradient grad_u, grad_v, grad_w;
        for( unsigned int d = 0; d < n_u_dofs; d++ )
          {
            libMesh::RealGradient u_gradphi( dphi_dxi[d][qp], dphi_deta[d][qp] );
            grad_u += u_coeffs(d)*u_gradphi;
            grad_v += v_coeffs(d)*u_gradphi;
            grad_w += w_coeffs(d)*u_gradphi;
          }

        libMesh::RealGradient dudxi( grad_u(0), grad_v(0), grad_w(0) );
        libMesh::RealGradient dudeta( grad_u(1), grad_v(1), grad_w(1) );

        libMesh::RealGradient A_1 = dxdxi[qp] + dudxi;
        libMesh::RealGradient A_2 = dxdeta[qp] + dudeta;

        libMesh::RealGradient A_3 = A_1.cross(A_2);

        // Compute pressure at this quadrature point
        libMesh::Real press = (*_pressure)(context,qp);

        // Small optimization
        libMesh::Real p_over_sa = press/sqrt_a;

        /* The formula here is actually
           P*\sqrt{\frac{A}{a}}*A_3, where A_3 is a unit vector
           But, |A_3| = \sqrt{A} so the normalizing part kills
           the \sqrt{A} in the numerator, so we can leave it out
           and *not* normalize A_3.
        */
        libMesh::RealGradient traction = p_over_sa*A_3;

        for (unsigned int i=0; i != n_u_dofs; i++)
          {
            // Small optimization
            libMesh::Real phi_times_jac = u_phi[i][qp]*JxW[qp];

            Fu(i) -= traction(0)*phi_times_jac;
            Fv(i) -= traction(1)*phi_times_jac;
            Fw(i) -= traction(2)*phi_times_jac;

            if( compute_jacobian )
              {
                for (unsigned int j=0; j != n_u_dofs; j++)
                  {
                    libMesh::RealGradient u_gradphi( dphi_dxi[j][qp], dphi_deta[j][qp] );

                    const libMesh::Real dt0_dv = p_over_sa*(u_gradphi(0)*A_2(2) - A_1(2)*u_gradphi(1));
                    const libMesh::Real dt0_dw = p_over_sa*(A_1(1)*u_gradphi(1) - u_gradphi(0)*A_2(1));

                    const libMesh::Real dt1_du = p_over_sa*(A_1(2)*u_gradphi(1) - u_gradphi(0)*A_2(2));
                    const libMesh::Real dt1_dw = p_over_sa*(u_gradphi(0)*A_2(0) - A_1(0)*u_gradphi(1));

                    const libMesh::Real dt2_du = p_over_sa*(u_gradphi(0)*A_2(1) - A_1(1)*u_gradphi(1));
                    const libMesh::Real dt2_dv = p_over_sa*(A_1(0)*u_gradphi(1) - u_gradphi(0)*A_2(0));

                    Kuv(i,j) -= dt0_dv*phi_times_jac;
                    Kuw(i,j) -= dt0_dw*phi_times_jac;

                    Kvu(i,j) -= dt1_du*phi_times_jac;
                    Kvw(i,j) -= dt1_dw*phi_times_jac;

                    Kwu(i,j) -= dt2_du*phi_times_jac;
                    Kwv(i,j) -= dt2_dv*phi_times_jac;
                  }
              }
          }
      }
  }
コード例 #6
0
  void ElasticMembraneConstantPressure::element_time_derivative( bool compute_jacobian,
                                                                 AssemblyContext& context,
                                                                 CachedValues& /*cache*/ )
  {
    const unsigned int n_u_dofs = context.get_dof_indices(_disp_vars.u()).size();

    const std::vector<libMesh::Real> &JxW =
      this->get_fe(context)->get_JxW();

    const std::vector<std::vector<libMesh::Real> >& u_phi =
      this->get_fe(context)->get_phi();

    libMesh::DenseSubVector<libMesh::Number> &Fu = context.get_elem_residual(_disp_vars.u());
    libMesh::DenseSubVector<libMesh::Number> &Fv = context.get_elem_residual(_disp_vars.v());
    libMesh::DenseSubVector<libMesh::Number> &Fw = context.get_elem_residual(_disp_vars.w());

    libMesh::DenseSubMatrix<libMesh::Number>& Kuv = context.get_elem_jacobian(_disp_vars.u(),_disp_vars.v());
    libMesh::DenseSubMatrix<libMesh::Number>& Kuw = context.get_elem_jacobian(_disp_vars.u(),_disp_vars.w());

    libMesh::DenseSubMatrix<libMesh::Number>& Kvu = context.get_elem_jacobian(_disp_vars.v(),_disp_vars.u());
    libMesh::DenseSubMatrix<libMesh::Number>& Kvw = context.get_elem_jacobian(_disp_vars.v(),_disp_vars.w());

    libMesh::DenseSubMatrix<libMesh::Number>& Kwu = context.get_elem_jacobian(_disp_vars.w(),_disp_vars.u());
    libMesh::DenseSubMatrix<libMesh::Number>& Kwv = context.get_elem_jacobian(_disp_vars.w(),_disp_vars.v());

    unsigned int n_qpoints = context.get_element_qrule().n_points();

    // All shape function gradients are w.r.t. master element coordinates
    const std::vector<std::vector<libMesh::Real> >& dphi_dxi =
      this->get_fe(context)->get_dphidxi();

    const std::vector<std::vector<libMesh::Real> >& dphi_deta =
      this->get_fe(context)->get_dphideta();

    const libMesh::DenseSubVector<libMesh::Number>& u_coeffs = context.get_elem_solution( _disp_vars.u() );
    const libMesh::DenseSubVector<libMesh::Number>& v_coeffs = context.get_elem_solution( _disp_vars.v() );
    const libMesh::DenseSubVector<libMesh::Number>& w_coeffs = context.get_elem_solution( _disp_vars.w() );

    const std::vector<libMesh::RealGradient>& dxdxi  = this->get_fe(context)->get_dxyzdxi();
    const std::vector<libMesh::RealGradient>& dxdeta = this->get_fe(context)->get_dxyzdeta();

    for (unsigned int qp=0; qp != n_qpoints; qp++)
      {
        // sqrt(det(a_cov)), a_cov being the covariant metric tensor of undeformed body
        libMesh::Real sqrt_a = sqrt( dxdxi[qp]*dxdxi[qp]*dxdeta[qp]*dxdeta[qp]
                                     - dxdxi[qp]*dxdeta[qp]*dxdeta[qp]*dxdxi[qp] );

        // Gradients are w.r.t. master element coordinates
        libMesh::Gradient grad_u, grad_v, grad_w;
        for( unsigned int d = 0; d < n_u_dofs; d++ )
          {
            libMesh::RealGradient u_gradphi( dphi_dxi[d][qp], dphi_deta[d][qp] );
            grad_u += u_coeffs(d)*u_gradphi;
            grad_v += v_coeffs(d)*u_gradphi;
            grad_w += w_coeffs(d)*u_gradphi;
          }

        libMesh::RealGradient dudxi( grad_u(0), grad_v(0), grad_w(0) );
        libMesh::RealGradient dudeta( grad_u(1), grad_v(1), grad_w(1) );

        libMesh::RealGradient A_1 = dxdxi[qp] + dudxi;
        libMesh::RealGradient A_2 = dxdeta[qp] + dudeta;

        libMesh::RealGradient A_3 = A_1.cross(A_2);

        /* The formula here is actually
           P*\sqrt{\frac{A}{a}}*A_3, where A_3 is a unit vector
           But, |A_3| = \sqrt{A} so the normalizing part kills
           the \sqrt{A} in the numerator, so we can leave it out
           and *not* normalize A_3.
         */
        libMesh::RealGradient traction = _pressure/sqrt_a*A_3;

        libMesh::Real jac = JxW[qp];

        for (unsigned int i=0; i != n_u_dofs; i++)
	  {
            Fu(i) -= traction(0)*u_phi[i][qp]*jac;

            Fv(i) -= traction(1)*u_phi[i][qp]*jac;

            Fw(i) -= traction(2)*u_phi[i][qp]*jac;

            if( compute_jacobian )
              {
                for (unsigned int j=0; j != n_u_dofs; j++)
                  {
                    libMesh::RealGradient u_gradphi( dphi_dxi[j][qp], dphi_deta[j][qp] );

                    const libMesh::Real dt0_dv = _pressure/sqrt_a*(u_gradphi(0)*A_2(2) - A_1(2)*u_gradphi(1));
                    const libMesh::Real dt0_dw = _pressure/sqrt_a*(A_1(1)*u_gradphi(1) - u_gradphi(0)*A_2(1));

                    const libMesh::Real dt1_du = _pressure/sqrt_a*(A_1(2)*u_gradphi(1) - u_gradphi(0)*A_2(2));
                    const libMesh::Real dt1_dw = _pressure/sqrt_a*(u_gradphi(0)*A_2(0) - A_1(0)*u_gradphi(1));

                    const libMesh::Real dt2_du = _pressure/sqrt_a*(u_gradphi(0)*A_2(1) - A_1(1)*u_gradphi(1));
                    const libMesh::Real dt2_dv = _pressure/sqrt_a*(A_1(0)*u_gradphi(1) - u_gradphi(0)*A_2(0));

                    Kuv(i,j) -= dt0_dv*u_phi[i][qp]*jac;
                    Kuw(i,j) -= dt0_dw*u_phi[i][qp]*jac;

                    Kvu(i,j) -= dt1_du*u_phi[i][qp]*jac;
                    Kvw(i,j) -= dt1_dw*u_phi[i][qp]*jac;

                    Kwu(i,j) -= dt2_du*u_phi[i][qp]*jac;
                    Kwv(i,j) -= dt2_dv*u_phi[i][qp]*jac;
                  }
              }
          }
      }

    return;
  }