riemannsolver_anisotropic.h

Go to the documentation of this file.

#include "../../../ExaHyPE/kernels/KernelUtils.h"
 
namespace Numerics {
  // Getter routines
 
  template <class Shortcuts>
  inline void compute_parameters(const double* Q, double& rho, double& cp, double cs[], int direction) {
    Shortcuts s;
    rho = Q[s.rho];
 
    cp = std::sqrt(Q[s.c + direction] / rho);
 
    switch (direction) {
    case 0:
      cs[0] = std::sqrt(Q[s.c + 3] / rho);
      cs[1] = std::sqrt(Q[s.c + 4] / rho);
      break;
    case 1:
      cs[0] = std::sqrt(Q[s.c + 5] / rho);
      cs[1] = std::sqrt(Q[s.c + 3] / rho);
      break;
    case 2:
      cs[0] = std::sqrt(Q[s.c + 4] / rho);
      cs[1] = std::sqrt(Q[s.c + 5] / rho);
      break;
    default:
      std::cout << "Direction : " << direction << " not defined" << std::endl;
      std::exit(1);
    }
  }
 
  inline void riemannSolver_boundary(
    int     faceIndex,
    double  r,
    double  vn,
    double  vm,
    double  vl,
    double  Tn,
    double  Tm,
    double  Tl,
    double  zp,
    double  zs[2],
    double& vn_hat,
    double& vm_hat,
    double& vl_hat,
    double& Tn_hat,
    double& Tm_hat,
    double& Tl_hat
  ) {
    // if (faceIndex % 2  == 0) { //left face
    if (faceIndex < Dimensions) { //left face
      riemannSolver_BC0(vn, Tn, zp, r, vn_hat, Tn_hat);
      riemannSolver_BC0(vm, Tm, zs[0], r, vm_hat, Tm_hat);
      riemannSolver_BC0(vl, Tl, zs[1], r, vl_hat, Tl_hat);
    }
 
    // if (faceIndex % 2 == 1) { //right face
    else { //right face
      riemannSolver_BCn(vn, Tn, zp, r, vn_hat, Tn_hat);
      riemannSolver_BCn(vm, Tm, zs[0], r, vm_hat, Tm_hat);
      riemannSolver_BCn(vl, Tl, zs[1], r, vl_hat, Tl_hat);
    }
  }
 
  template <class Shortcuts, int order, int numberOfVariables, int numberOfParameters>
  void riemannSolver(
    double*             FL,
    double*             FR,
    const double* const QL,
    const double* const QR,
    const double        dt,
    const int           direction,
    bool                isBoundaryFace,
    int                 faceIndex
  ) {
 
    constexpr int numberOfData = numberOfVariables + numberOfParameters;
    constexpr int basisSize    = order + 1;
 
    kernels::idx3 idx_QLR(basisSize, basisSize, numberOfData);
    kernels::idx3 idx_FLR(basisSize, basisSize, numberOfVariables);
 
    double FLn, FLm, FLl, FRn, FRm, FRl;
    double FLx, FLy, FLz, FRx, FRy, FRz;
    double FL_n, FL_m, FL_l, FR_n, FR_m, FR_l;
    double FL_x, FL_y, FL_z, FR_x, FR_y, FR_z;
 
    Shortcuts s;
    for (int i = 0; i < basisSize; i++) {
      for (int j = 0; j < basisSize; j++) {
 
        const double* Q_p = QR + idx_QLR(i, j, 0);
        const double* Q_m = QL + idx_QLR(i, j, 0);
 
        double* F_m = FL + idx_FLR(i, j, 0);
        double* F_p = FR + idx_FLR(i, j, 0);
        double  rho_m, cp_m, cs_m[2], c11_m, c22_m, c33_m, c44_m, c55_m, c66_m, c12_m, c13_m, c23_m;
        double  rho_p, cp_p, cs_p[2], c11_p, c22_p, c33_p, c44_p, c55_p, c66_p, c12_p, c13_p, c23_p;
 
        Numerics::get_stiffness_tensor<Shortcuts>(Q_m, c11_m, c22_m, c33_m, c44_m, c55_m, c66_m, c12_m, c13_m, c23_m);
        Numerics::get_stiffness_tensor<Shortcuts>(Q_p, c11_p, c22_p, c33_p, c44_p, c55_p, c66_p, c12_p, c13_p, c23_p);
 
        compute_parameters<Shortcuts>(Q_m, rho_m, cp_m, cs_m, direction);
        compute_parameters<Shortcuts>(Q_p, rho_p, cp_p, cs_p, direction);
 
        double n_m[3], m_m[3], l_m[3];
        double n_p[3], m_p[3], l_p[3];
        double norm_p, norm_m;
 
        get_normals<Shortcuts>(Q_m, direction, norm_m, n_m);
        get_normals<Shortcuts>(Q_p, direction, norm_p, n_p);
 
        double Tx_m, Ty_m, Tz_m;
        double Tx_p, Ty_p, Tz_p;
        compute_tractions<Shortcuts>(Q_p, n_p, Tx_p, Ty_p, Tz_p);
        compute_tractions<Shortcuts>(Q_m, n_m, Tx_m, Ty_m, Tz_m);
 
        double vx_m, vy_m, vz_m;
        double vx_p, vy_p, vz_p;
        get_velocities<Shortcuts>(Q_p, vx_p, vy_p, vz_p);
        get_velocities<Shortcuts>(Q_m, vx_m, vy_m, vz_m);
 
        create_local_basis(n_p, m_p, l_p);
        create_local_basis(n_m, m_m, l_m);
 
        double Tn_m, Tm_m, Tl_m;
        double Tn_p, Tm_p, Tl_p;
 
        // rotate fields into l, m, n basis
        rotate_into_orthogonal_basis(n_m, m_m, l_m, Tx_m, Ty_m, Tz_m, Tn_m, Tm_m, Tl_m);
        rotate_into_orthogonal_basis(n_p, m_p, l_p, Tx_p, Ty_p, Tz_p, Tn_p, Tm_p, Tl_p);
 
        double vn_m, vm_m, vl_m;
        double vn_p, vm_p, vl_p;
        rotate_into_orthogonal_basis(n_m, m_m, l_m, vx_m, vy_m, vz_m, vn_m, vm_m, vl_m);
        rotate_into_orthogonal_basis(n_p, m_p, l_p, vx_p, vy_p, vz_p, vn_p, vm_p, vl_p);
 
        // extract local s-wave and p-wave impedances
        double zs_m[2];
        double zs_p[2];
 
        zs_m[0] = rho_m * cs_m[0];
        zs_m[1] = rho_m * cs_m[1];
 
        zs_p[0] = rho_m * cs_p[0];
        zs_p[1] = rho_m * cs_p[1];
 
        double zp_m = rho_m * cp_m;
        double zp_p = rho_p * cp_p;
 
        // impedance must be greater than zero !
        assertion3(!(zp_p <= 0.0 || zp_m <= 0.0), "Impedance must be greater than zero !", zp_p, zs_p);
 
        // generate interface data preserving the amplitude of the outgoing charactertritics
        // and satisfying interface conditions exactly.
        double vn_hat_p, vm_hat_p, vl_hat_p;
        double Tn_hat_p, Tm_hat_p, Tl_hat_p;
        double vn_hat_m, vm_hat_m, vl_hat_m;
        double Tn_hat_m, Tm_hat_m, Tl_hat_m;
 
        if (isBoundaryFace) {
          // 0 absorbing 1 free surface
          double r = faceIndex == 2 ? 1 : 0;
          //    double r=1.;
          riemannSolver_boundary(
            faceIndex,
            r,
            vn_m,
            vm_m,
            vl_m,
            Tn_m,
            Tm_m,
            Tl_m,
            zp_m,
            zs_m,
            vn_hat_m,
            vm_hat_m,
            vl_hat_m,
            Tn_hat_m,
            Tm_hat_m,
            Tl_hat_m
          );
          riemannSolver_boundary(
            faceIndex,
            r,
            vn_p,
            vm_p,
            vl_p,
            Tn_p,
            Tm_p,
            Tl_p,
            zp_p,
            zs_p,
            vn_hat_p,
            vm_hat_p,
            vl_hat_p,
            Tn_hat_p,
            Tm_hat_p,
            Tl_hat_p
          );
        } else {
          riemannSolver_Nodal(vn_p, vn_m, Tn_p, Tn_m, zp_p, zp_m, vn_hat_p, vn_hat_m, Tn_hat_p, Tn_hat_m);
          riemannSolver_Nodal(vm_p, vm_m, Tm_p, Tm_m, zs_p[0], zs_m[0], vm_hat_p, vm_hat_m, Tm_hat_p, Tm_hat_m);
          riemannSolver_Nodal(vl_p, vl_m, Tl_p, Tl_m, zs_p[1], zs_m[1], vl_hat_p, vl_hat_m, Tl_hat_p, Tl_hat_m);
        }
 
        // generate fluctuations in the local basis coordinates: n, m, l
        compute_fluctuations_left(zp_m, Tn_m, Tn_hat_m, vn_m, vn_hat_m, FLn);
        compute_fluctuations_left(zs_m[0], Tm_m, Tm_hat_m, vm_m, vm_hat_m, FLm);
        compute_fluctuations_left(zs_m[1], Tl_m, Tl_hat_m, vl_m, vl_hat_m, FLl);
 
        compute_fluctuations_right(zp_p, Tn_p, Tn_hat_p, vn_p, vn_hat_p, FRn);
        compute_fluctuations_right(zs_p[0], Tm_p, Tm_hat_p, vm_p, vm_hat_p, FRm);
        compute_fluctuations_right(zs_p[1], Tl_p, Tl_hat_p, vl_p, vl_hat_p, FRl);
 
        // Consider acoustic boundary
        FL_n = FLn / zp_m;
        if (zs_m[0] > 0) {
          FL_m = FLm / zs_m[0];
        } else {
          FL_m = 0;
        }
        if (zs_m[1] > 0) {
          FL_l = FLl / zs_m[1];
        } else {
          FL_l = 0;
        }
 
        FR_n = FRn / zp_p;
        if (zs_p[0] > 0) {
          FR_m = FRm / zs_p[0];
        } else {
          FR_m = 0;
        }
 
        if (zs_p[1] > 0) {
          FR_l = FRl / zs_p[1];
        } else {
          FR_l = 0;
        }
 
        // rotate back to the physical coordinates x, y, z
        rotate_into_physical_basis(n_m, m_m, l_m, FLn, FLm, FLl, FLx, FLy, FLz);
        rotate_into_physical_basis(n_p, m_p, l_p, FRn, FRm, FRl, FRx, FRy, FRz);
        rotate_into_physical_basis(n_m, m_m, l_m, FL_n, FL_m, FL_l, FL_x, FL_y, FL_z);
        rotate_into_physical_basis(n_p, m_p, l_p, FR_n, FR_m, FR_l, FR_x, FR_y, FR_z);
 
        // construct flux fluctuation vectors obeying the eigen structure of the PDE
        // and choose physically motivated penalties such that we can prove
        // numerical stability.
        F_p[s.v + 0] = norm_p / rho_p * FRx;
        F_m[s.v + 0] = norm_m / rho_m * FLx;
 
        F_p[s.v + 1] = norm_p / rho_p * FRy;
        F_m[s.v + 1] = norm_m / rho_m * FLy;
 
        F_p[s.v + 2] = norm_p / rho_p * FRz;
        F_m[s.v + 2] = norm_m / rho_m * FLz;
 
        F_m[s.sigma + 0] = norm_m * (c11_m * n_m[0] * FL_x + c12_m * n_m[1] * FL_y + c13_m * n_m[2] * FL_z);
        F_m[s.sigma + 1] = norm_m * (c12_m * n_m[0] * FL_x + c22_m * n_m[1] * FL_y + c23_m * n_m[2] * FL_z);
        F_m[s.sigma + 2] = norm_m * (c13_m * n_m[0] * FL_x + c23_m * n_m[1] * FL_y + c33_m * n_m[2] * FL_z);
 
        F_p[s.sigma + 0] = -norm_p * (c11_p * n_p[0] * FR_x + c12_p * n_p[1] * FR_y + c13_p * n_p[2] * FR_z);
        F_p[s.sigma + 1] = -norm_p * (c12_p * n_p[0] * FR_x + c22_p * n_p[1] * FR_y + c23_p * n_p[2] * FR_z);
        F_p[s.sigma + 2] = -norm_p * (c13_p * n_p[0] * FR_x + c23_p * n_p[1] * FR_y + c33_p * n_p[2] * FR_z);
 
        F_m[s.sigma + 3] = norm_m * c44_m * (n_m[1] * FL_x + n_m[0] * FL_y);
        F_m[s.sigma + 4] = norm_m * c55_m * (n_m[2] * FL_x + n_m[0] * FL_z);
        F_m[s.sigma + 5] = norm_m * c66_m * (n_m[2] * FL_y + n_m[1] * FL_z);
 
        F_p[s.sigma + 3] = -norm_p * c44_p * (n_p[1] * FR_x + n_p[0] * FR_y);
        F_p[s.sigma + 4] = -norm_p * c55_p * (n_p[2] * FR_x + n_p[0] * FR_z);
        F_p[s.sigma + 5] = -norm_p * c66_p * (n_p[2] * FR_y + n_p[1] * FR_z);
      }
    }
  }
} // namespace Numerics