1 // SPDX-FileCopyrightText: Copyright (c) 2017-2024, HONEE contributors. 2 // SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause 3 4 /// @file 5 /// Helper functions for computing stabilization terms of a newtonian simulation 6 #include <ceed/types.h> 7 8 #include "newtonian_state.h" 9 10 // ***************************************************************************** 11 // Helper function for computing the variation in primitive variables, given Tau_d 12 // ***************************************************************************** 13 CEED_QFUNCTION_HELPER void dYFromTau(const CeedScalar Y[5], const CeedScalar Tau_d[3], CeedScalar dY[5]) { 14 dY[0] = Tau_d[0] * Y[0]; 15 dY[1] = Tau_d[1] * Y[1]; 16 dY[2] = Tau_d[1] * Y[2]; 17 dY[3] = Tau_d[1] * Y[3]; 18 dY[4] = Tau_d[2] * Y[4]; 19 } 20 21 // ***************************************************************************** 22 // Helper functions for computing the stabilization terms 23 // ***************************************************************************** 24 CEED_QFUNCTION_HELPER void StabilizationMatrix(const NewtonianIdealGasContext gas, const State s, const CeedScalar Tau_d[3], 25 const CeedScalar strong_residual[5], CeedScalar stab[5][3]) { 26 CeedScalar dY[5]; 27 StateConservative dF[3]; 28 // Zero stab so all future terms can safely sum into it 29 SetValueN((CeedScalar *)stab, 0, 15); 30 dYFromTau(strong_residual, Tau_d, dY); 31 State ds = StateFromY_fwd(gas, s, dY); 32 FluxInviscid_fwd(gas, s, ds, dF); 33 for (CeedInt i = 0; i < 3; i++) { 34 CeedScalar dF_i[5]; 35 UnpackState_U(dF[i], dF_i); 36 for (CeedInt j = 0; j < 5; j++) stab[j][i] += dF_i[j]; 37 } 38 } 39 40 CEED_QFUNCTION_HELPER void Stabilization(const NewtonianIdealGasContext gas, const State s, const CeedScalar Tau_d[3], const State ds[3], 41 const CeedScalar U_dot[5], const CeedScalar body_force[5], const CeedScalar divFdiff[5], 42 CeedScalar stab[5][3]) { 43 // -- Stabilization method: none (Galerkin), SU, or SUPG 44 CeedScalar strong_residual[5] = {0}; 45 switch (gas->stabilization) { 46 case STAB_NONE: 47 break; 48 case STAB_SU: 49 FluxInviscidStrong(gas, s, ds, strong_residual); 50 break; 51 case STAB_SUPG: 52 FluxInviscidStrong(gas, s, ds, strong_residual); 53 for (CeedInt j = 0; j < 5; j++) strong_residual[j] += U_dot[j] - body_force[j] + divFdiff[j]; 54 break; 55 } 56 StabilizationMatrix(gas, s, Tau_d, strong_residual, stab); 57 } 58 59 // ***************************************************************************** 60 // Helper function for computing Tau elements (stabilization constant) 61 // Model from: 62 // PHASTA 63 // 64 // Tau[i] = itau=0 which is diagonal-Shakib (3 values still but not spatial) 65 // ***************************************************************************** 66 CEED_QFUNCTION_HELPER void Tau_diagPrim(NewtonianIdealGasContext gas, State s, const CeedScalar dXdx[3][3], const CeedScalar dt, 67 CeedScalar Tau_d[3]) { 68 // Context 69 const CeedScalar Ctau_t = gas->Ctau_t; 70 const CeedScalar Ctau_v = gas->Ctau_v; 71 const CeedScalar Ctau_C = gas->Ctau_C; 72 const CeedScalar Ctau_M = gas->Ctau_M; 73 const CeedScalar Ctau_E = gas->Ctau_E; 74 const CeedScalar cv = gas->cv; 75 const CeedScalar mu = gas->mu; 76 const CeedScalar rho = s.U.density; 77 78 CeedScalar tau; 79 CeedScalar dts; 80 CeedScalar fact; 81 82 CeedScalar gijd_mat[3][3] = {{0.}}, velocity_term; 83 MatMat3(dXdx, dXdx, CEED_TRANSPOSE, CEED_NOTRANSPOSE, gijd_mat); 84 85 dts = Ctau_t / dt; 86 87 { // u_i g_ij u_j 88 CeedScalar gij_uj[3] = {0.}; 89 MatVec3(gijd_mat, s.Y.velocity, CEED_NOTRANSPOSE, gij_uj); 90 velocity_term = Dot3(s.Y.velocity, gij_uj); 91 } 92 93 tau = Square(rho) * (4. * Square(dts) + velocity_term) + Ctau_v * Square(mu) * DotN((CeedScalar *)gijd_mat, (CeedScalar *)gijd_mat, 9); 94 95 fact = sqrt(tau); 96 97 Tau_d[0] = Ctau_C * fact / (rho * (gijd_mat[0][0] + gijd_mat[1][1] + gijd_mat[2][2])) * 0.125; 98 Tau_d[1] = Ctau_M / fact; 99 Tau_d[2] = Ctau_E / (fact * cv); 100 101 // consider putting back the way I initially had it 102 // Ctau_E * Tau_d[1] /cv to avoid a division if the compiler is smart enough to see that cv IS a constant that it could invert once for all elements 103 // but in that case energy tau is scaled by the product of Ctau_E * Ctau_M 104 // OR we could absorb cv into Ctau_E but this puts more burden on user to know how to change constants with a change of fluid or units. Same for 105 // Ctau_v * mu * mu IF AND ONLY IF we don't add viscosity law =f(T) 106 } 107