1 // Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and other CEED contributors. 2 // All Rights Reserved. See the top-level LICENSE and NOTICE files for details. 3 // 4 // SPDX-License-Identifier: BSD-2-Clause 5 // 6 // This file is part of CEED: http://github.com/ceed 7 8 /// @file 9 /// Utility functions for setting up Blasius Boundary Layer 10 11 #include "../qfunctions/blasius.h" 12 13 #include <ceed.h> 14 #include <petscdm.h> 15 #include <petscdt.h> 16 17 #include "../navierstokes.h" 18 #include "stg_shur14.h" 19 20 PetscErrorCode CompressibleBlasiusResidual(SNES snes, Vec X, Vec R, void *ctx) { 21 const BlasiusContext blasius = (BlasiusContext)ctx; 22 const PetscScalar *Tf, *Th; // Chebyshev coefficients 23 PetscScalar *r, f[4], h[4]; 24 PetscInt N = blasius->n_cheb; 25 State S_infty = blasius->S_infty; 26 CeedScalar U_infty = sqrt(Dot3(S_infty.Y.velocity, S_infty.Y.velocity)); 27 28 PetscFunctionBeginUser; 29 PetscScalar Ma = Mach(&blasius->newtonian_ctx, S_infty.Y.temperature, U_infty), Pr = Prandtl(&blasius->newtonian_ctx), 30 gamma = HeatCapacityRatio(&blasius->newtonian_ctx); 31 32 PetscCall(VecGetArrayRead(X, &Tf)); 33 Th = Tf + N; 34 PetscCall(VecGetArray(R, &r)); 35 36 // Left boundary conditions f = f' = 0 37 ChebyshevEval(N, Tf, -1., blasius->eta_max, f); 38 r[0] = f[0]; 39 r[1] = f[1]; 40 41 // f - right end boundary condition 42 ChebyshevEval(N, Tf, 1., blasius->eta_max, f); 43 r[2] = f[1] - 1.; 44 45 for (int i = 0; i < N - 3; i++) { 46 ChebyshevEval(N, Tf, blasius->X[i], blasius->eta_max, f); 47 ChebyshevEval(N - 1, Th, blasius->X[i], blasius->eta_max, h); 48 // mu and rho generally depend on h. 49 // We naively assume constant mu. 50 // For an ideal gas at constant pressure, density is inversely proportional to enthalpy. 51 // The *_tilde values are *relative* to their freestream values, and we proved first derivatives here. 52 const PetscScalar mu_tilde[2] = {1, 0}; 53 const PetscScalar rho_tilde[2] = {1 / h[0], -h[1] / PetscSqr(h[0])}; 54 const PetscScalar mu_rho_tilde[2] = { 55 mu_tilde[0] * rho_tilde[0], 56 mu_tilde[1] * rho_tilde[0] + mu_tilde[0] * rho_tilde[1], 57 }; 58 r[3 + i] = 2 * (mu_rho_tilde[0] * f[3] + mu_rho_tilde[1] * f[2]) + f[2] * f[0]; 59 r[N + 2 + i] = (mu_rho_tilde[0] * h[2] + mu_rho_tilde[1] * h[1]) + Pr * f[0] * h[1] + Pr * (gamma - 1) * mu_rho_tilde[0] * PetscSqr(Ma * f[2]); 60 } 61 62 // h - left end boundary condition 63 ChebyshevEval(N - 1, Th, -1., blasius->eta_max, h); 64 r[N] = h[0] - blasius->T_wall / S_infty.Y.temperature; 65 66 // h - right end boundary condition 67 ChebyshevEval(N - 1, Th, 1., blasius->eta_max, h); 68 r[N + 1] = h[0] - 1.; 69 70 // Restore vectors 71 PetscCall(VecRestoreArrayRead(X, &Tf)); 72 PetscCall(VecRestoreArray(R, &r)); 73 PetscFunctionReturn(PETSC_SUCCESS); 74 } 75 76 PetscErrorCode ComputeChebyshevCoefficients(BlasiusContext blasius) { 77 SNES snes; 78 Vec sol, res; 79 PetscReal *w; 80 PetscInt N = blasius->n_cheb; 81 SNESConvergedReason reason; 82 const PetscScalar *cheb_coefs; 83 84 PetscFunctionBeginUser; 85 // Allocate memory 86 PetscCall(PetscMalloc2(N - 3, &blasius->X, N - 3, &w)); 87 PetscCall(PetscDTGaussQuadrature(N - 3, -1., 1., blasius->X, w)); 88 89 // Snes solve 90 PetscCall(SNESCreate(PETSC_COMM_SELF, &snes)); 91 PetscCall(VecCreate(PETSC_COMM_SELF, &sol)); 92 PetscCall(VecSetSizes(sol, PETSC_DECIDE, 2 * N - 1)); 93 PetscCall(VecSetFromOptions(sol)); 94 // Constant relative enthalpy 1 as initial guess 95 PetscCall(VecSetValue(sol, N, 1., INSERT_VALUES)); 96 PetscCall(VecDuplicate(sol, &res)); 97 PetscCall(SNESSetFunction(snes, res, CompressibleBlasiusResidual, blasius)); 98 PetscCall(SNESSetOptionsPrefix(snes, "chebyshev_")); 99 PetscCall(SNESSetFromOptions(snes)); 100 PetscCall(SNESSolve(snes, NULL, sol)); 101 PetscCall(SNESGetConvergedReason(snes, &reason)); 102 PetscCheck(reason >= 0, PETSC_COMM_WORLD, PETSC_ERR_CONV_FAILED, "The Chebyshev solve failed.\n"); 103 104 // Assign Chebyshev coefficients 105 PetscCall(VecGetArrayRead(sol, &cheb_coefs)); 106 for (int i = 0; i < N; i++) blasius->Tf_cheb[i] = cheb_coefs[i]; 107 for (int i = 0; i < N - 1; i++) blasius->Th_cheb[i] = cheb_coefs[i + N]; 108 109 // Destroy objects 110 PetscCall(PetscFree2(blasius->X, w)); 111 PetscCall(VecDestroy(&sol)); 112 PetscCall(VecDestroy(&res)); 113 PetscCall(SNESDestroy(&snes)); 114 PetscFunctionReturn(PETSC_SUCCESS); 115 } 116 117 static PetscErrorCode GetYNodeLocs(const MPI_Comm comm, const char path[PETSC_MAX_PATH_LEN], PetscReal **pynodes, PetscInt *nynodes) { 118 int ndims, dims[2]; 119 FILE *fp; 120 const PetscInt char_array_len = 512; 121 char line[char_array_len]; 122 char **array; 123 PetscReal *node_locs; 124 125 PetscFunctionBeginUser; 126 PetscCall(PetscFOpen(comm, path, "r", &fp)); 127 PetscCall(PetscSynchronizedFGets(comm, fp, char_array_len, line)); 128 PetscCall(PetscStrToArray(line, ' ', &ndims, &array)); 129 130 for (PetscInt i = 0; i < ndims; i++) dims[i] = atoi(array[i]); 131 if (ndims < 2) dims[1] = 1; // Assume 1 column of data is not otherwise specified 132 *nynodes = dims[0]; 133 PetscCall(PetscMalloc1(*nynodes, &node_locs)); 134 135 for (PetscInt i = 0; i < dims[0]; i++) { 136 PetscCall(PetscSynchronizedFGets(comm, fp, char_array_len, line)); 137 PetscCall(PetscStrToArray(line, ' ', &ndims, &array)); 138 PetscCheck(ndims == dims[1], comm, PETSC_ERR_FILE_UNEXPECTED, 139 "Line %" PetscInt_FMT " of %s does not contain correct number of columns (%d instead of %d)", i, path, ndims, dims[1]); 140 141 node_locs[i] = (PetscReal)atof(array[0]); 142 } 143 PetscCall(PetscFClose(comm, fp)); 144 *pynodes = node_locs; 145 PetscFunctionReturn(PETSC_SUCCESS); 146 } 147 148 /* \brief Modify the domain and mesh for blasius 149 * 150 * Modifies mesh such that `N` elements are within `refine_height` with a geometric growth ratio of `growth`. Excess elements are then distributed 151 * linearly in logspace to the top surface. 152 * 153 * The top surface is also angled downwards, so that it may be used as an outflow. 154 * It's angle is controlled by `top_angle` (in units of degrees). 155 * 156 * If `node_locs` is not NULL, then the nodes will be placed at `node_locs` locations. 157 * If it is NULL, then the modified coordinate values will be set in the array, along with `num_node_locs`. 158 */ 159 static PetscErrorCode ModifyMesh(MPI_Comm comm, DM dm, PetscInt dim, PetscReal growth, PetscInt N, PetscReal refine_height, PetscReal top_angle, 160 PetscReal *node_locs[], PetscInt *num_node_locs) { 161 PetscInt narr, ncoords; 162 PetscReal domain_min[3], domain_max[3], domain_size[3]; 163 PetscScalar *arr_coords; 164 Vec vec_coords; 165 166 PetscFunctionBeginUser; 167 PetscReal angle_coeff = tan(top_angle * (M_PI / 180)); 168 // Get domain boundary information 169 PetscCall(DMGetBoundingBox(dm, domain_min, domain_max)); 170 for (PetscInt i = 0; i < 3; i++) domain_size[i] = domain_max[i] - domain_min[i]; 171 172 // Get coords array from DM 173 PetscCall(DMGetCoordinatesLocal(dm, &vec_coords)); 174 PetscCall(VecGetLocalSize(vec_coords, &narr)); 175 PetscCall(VecGetArray(vec_coords, &arr_coords)); 176 177 PetscScalar(*coords)[dim] = (PetscScalar(*)[dim])arr_coords; 178 ncoords = narr / dim; 179 180 // Get mesh information 181 PetscInt nmax = 3, faces[3]; 182 PetscCall(PetscOptionsGetIntArray(NULL, NULL, "-dm_plex_box_faces", faces, &nmax, NULL)); 183 // Get element size of the box mesh, for indexing each node 184 const PetscReal dybox = domain_size[1] / faces[1]; 185 186 if (!*node_locs) { 187 // Calculate the first element height 188 PetscReal dy1 = refine_height * (growth - 1) / (pow(growth, N) - 1); 189 190 // Calculate log of sizing outside BL 191 PetscReal logdy = (log(domain_max[1]) - log(refine_height)) / (faces[1] - N); 192 193 *num_node_locs = faces[1] + 1; 194 PetscReal *temp_node_locs; 195 PetscCall(PetscMalloc1(*num_node_locs, &temp_node_locs)); 196 197 for (PetscInt i = 0; i < ncoords; i++) { 198 PetscInt y_box_index = round(coords[i][1] / dybox); 199 if (y_box_index <= N) { 200 coords[i][1] = 201 (1 - (coords[i][0] - domain_min[0]) * angle_coeff / domain_max[1]) * dy1 * (pow(growth, coords[i][1] / dybox) - 1) / (growth - 1); 202 } else { 203 PetscInt j = y_box_index - N; 204 coords[i][1] = (1 - (coords[i][0] - domain_min[0]) * angle_coeff / domain_max[1]) * exp(log(refine_height) + logdy * j); 205 } 206 if (coords[i][0] == domain_min[0] && coords[i][2] == domain_min[2]) temp_node_locs[y_box_index] = coords[i][1]; 207 } 208 209 *node_locs = temp_node_locs; 210 } else { 211 PetscCheck(*num_node_locs >= faces[1] + 1, comm, PETSC_ERR_FILE_UNEXPECTED, 212 "The y_node_locs_path has too few locations; There are %" PetscInt_FMT " + 1 nodes, but only %" PetscInt_FMT " locations given", 213 faces[1] + 1, *num_node_locs); 214 if (*num_node_locs > faces[1] + 1) { 215 PetscCall(PetscPrintf(comm, 216 "WARNING: y_node_locs_path has more locations (%" PetscInt_FMT ") " 217 "than the mesh has nodes (%" PetscInt_FMT "). This maybe unintended.\n", 218 *num_node_locs, faces[1] + 1)); 219 } 220 PetscScalar max_y = (*node_locs)[faces[1]]; 221 222 for (PetscInt i = 0; i < ncoords; i++) { 223 // Determine which y-node we're at 224 PetscInt y_box_index = round(coords[i][1] / dybox); 225 coords[i][1] = (1 - (coords[i][0] - domain_min[0]) * angle_coeff / max_y) * (*node_locs)[y_box_index]; 226 } 227 } 228 229 PetscCall(VecRestoreArray(vec_coords, &arr_coords)); 230 PetscCall(DMSetCoordinatesLocal(dm, vec_coords)); 231 PetscFunctionReturn(PETSC_SUCCESS); 232 } 233 234 PetscErrorCode NS_BLASIUS(ProblemData problem, DM dm, void *ctx, SimpleBC bc) { 235 User user = *(User *)ctx; 236 MPI_Comm comm = user->comm; 237 Ceed ceed = user->ceed; 238 PetscBool use_stg = PETSC_FALSE; 239 BlasiusContext blasius_ctx; 240 NewtonianIdealGasContext newtonian_ig_ctx; 241 CeedQFunctionContext blasius_context; 242 243 PetscFunctionBeginUser; 244 PetscCall(NS_NEWTONIAN_IG(problem, dm, ctx, bc)); 245 PetscCall(PetscCalloc1(1, &blasius_ctx)); 246 247 // ------------------------------------------------------ 248 // SET UP Blasius 249 // ------------------------------------------------------ 250 problem->ics.qfunction = ICsBlasius; 251 problem->ics.qfunction_loc = ICsBlasius_loc; 252 253 CeedScalar U_inf = 40; // m/s 254 CeedScalar T_inf = 288.; // K 255 CeedScalar T_wall = 288.; // K 256 CeedScalar delta0 = 4.2e-3; // m 257 CeedScalar P_inf = 1.01e5; // Pa 258 PetscInt N = 20; // Number of Chebyshev terms 259 PetscBool weakT = PETSC_FALSE; // weak density or temperature 260 PetscReal mesh_refine_height = 5.9e-4; // m 261 PetscReal mesh_growth = 1.08; // [-] 262 PetscInt mesh_Ndelta = 45; // [-] 263 PetscReal mesh_top_angle = 5; // degrees 264 char mesh_ynodes_path[PETSC_MAX_PATH_LEN] = ""; 265 PetscBool P0_set; 266 267 PetscOptionsBegin(comm, NULL, "Options for BLASIUS problem", NULL); 268 PetscCall(PetscOptionsBool("-weakT", "Change from rho weak to T weak at inflow", NULL, weakT, &weakT, NULL)); 269 PetscCall(PetscOptionsScalar("-velocity_infinity", "Velocity at boundary layer edge", NULL, U_inf, &U_inf, NULL)); 270 PetscCall(PetscOptionsScalar("-temperature_infinity", "Temperature at boundary layer edge", NULL, T_inf, &T_inf, NULL)); 271 PetscCall(PetscOptionsHasName(NULL, NULL, "-P0", &P0_set)); // For maintaining behavior of -P0 flag (which is deprecated) 272 PetscCall( 273 PetscOptionsDeprecated("-P0", "-pressure_infinity", "libCEED 0.12.0", 274 "Use -pressure_infinity to set pressure at boundary layer edge and -idl_pressure to set the IDL reference pressure")); 275 PetscCall(PetscOptionsScalar("-pressure_infinity", "Pressure at boundary layer edge", NULL, P_inf, &P_inf, NULL)); 276 PetscCall(PetscOptionsScalar("-temperature_wall", "Temperature at wall", NULL, T_wall, &T_wall, NULL)); 277 PetscCall(PetscOptionsScalar("-delta0", "Boundary layer height at inflow", NULL, delta0, &delta0, NULL)); 278 PetscCall(PetscOptionsInt("-n_chebyshev", "Number of Chebyshev terms", NULL, N, &N, NULL)); 279 PetscCheck(3 <= N && N <= BLASIUS_MAX_N_CHEBYSHEV, comm, PETSC_ERR_ARG_OUTOFRANGE, "-n_chebyshev %" PetscInt_FMT " must be in range [3, %d]", N, 280 BLASIUS_MAX_N_CHEBYSHEV); 281 if (user->app_ctx->mesh_transform_type == MESH_TRANSFORM_PLATEMESH) { 282 PetscCall(PetscOptionsBoundedInt("-platemesh_Ndelta", "Velocity at boundary layer edge", NULL, mesh_Ndelta, &mesh_Ndelta, NULL, 1)); 283 PetscCall(PetscOptionsScalar("-platemesh_refine_height", "Height of boundary layer mesh refinement", NULL, mesh_refine_height, 284 &mesh_refine_height, NULL)); 285 PetscCall(PetscOptionsScalar("-platemesh_growth", "Geometric growth rate of boundary layer mesh", NULL, mesh_growth, &mesh_growth, NULL)); 286 PetscCall( 287 PetscOptionsScalar("-platemesh_top_angle", "Geometric top_angle rate of boundary layer mesh", NULL, mesh_top_angle, &mesh_top_angle, NULL)); 288 PetscCall(PetscOptionsString("-platemesh_y_node_locs_path", 289 "Path to file with y node locations. " 290 "If empty, will use the algorithmic mesh warping.", 291 NULL, mesh_ynodes_path, mesh_ynodes_path, sizeof(mesh_ynodes_path), NULL)); 292 } 293 PetscCall(PetscOptionsBool("-stg_use", "Use STG inflow boundary condition", NULL, use_stg, &use_stg, NULL)); 294 PetscOptionsEnd(); 295 296 PetscScalar meter = user->units->meter; 297 PetscScalar second = user->units->second; 298 PetscScalar Kelvin = user->units->Kelvin; 299 PetscScalar Pascal = user->units->Pascal; 300 301 T_inf *= Kelvin; 302 T_wall *= Kelvin; 303 P_inf *= Pascal; 304 U_inf *= meter / second; 305 delta0 *= meter; 306 307 if (user->app_ctx->mesh_transform_type == MESH_TRANSFORM_PLATEMESH) { 308 PetscReal *mesh_ynodes = NULL; 309 PetscInt mesh_nynodes = 0; 310 if (strcmp(mesh_ynodes_path, "")) PetscCall(GetYNodeLocs(comm, mesh_ynodes_path, &mesh_ynodes, &mesh_nynodes)); 311 PetscCall(ModifyMesh(comm, dm, problem->dim, mesh_growth, mesh_Ndelta, mesh_refine_height, mesh_top_angle, &mesh_ynodes, &mesh_nynodes)); 312 PetscCall(PetscFree(mesh_ynodes)); 313 } 314 315 // Some properties depend on parameters from NewtonianIdealGas 316 PetscCallCeed(ceed, CeedQFunctionContextGetData(problem->apply_vol_rhs.qfunction_context, CEED_MEM_HOST, &newtonian_ig_ctx)); 317 318 StatePrimitive Y_inf = { 319 .pressure = P_inf, .velocity = {U_inf, 0, 0}, 320 .temperature = T_inf 321 }; 322 State S_infty = StateFromPrimitive(newtonian_ig_ctx, Y_inf); 323 324 blasius_ctx->weakT = weakT; 325 blasius_ctx->T_wall = T_wall; 326 blasius_ctx->delta0 = delta0; 327 blasius_ctx->S_infty = S_infty; 328 blasius_ctx->n_cheb = N; 329 blasius_ctx->implicit = user->phys->implicit; 330 if (P0_set) newtonian_ig_ctx->idl_pressure = P_inf; // For maintaining behavior of -P0 flag (which is deprecated) 331 blasius_ctx->newtonian_ctx = *newtonian_ig_ctx; 332 333 { 334 PetscReal domain_min[3], domain_max[3]; 335 PetscCall(DMGetBoundingBox(dm, domain_min, domain_max)); 336 blasius_ctx->x_inflow = domain_min[0]; 337 blasius_ctx->eta_max = 5 * domain_max[1] / blasius_ctx->delta0; 338 } 339 PetscBool diff_filter_mms = PETSC_FALSE; 340 PetscCall(PetscOptionsGetBool(NULL, NULL, "-diff_filter_mms", &diff_filter_mms, NULL)); 341 if (!use_stg && !diff_filter_mms) PetscCall(ComputeChebyshevCoefficients(blasius_ctx)); 342 343 PetscCallCeed(ceed, CeedQFunctionContextRestoreData(problem->apply_vol_rhs.qfunction_context, &newtonian_ig_ctx)); 344 345 PetscCallCeed(ceed, CeedQFunctionContextCreate(user->ceed, &blasius_context)); 346 PetscCallCeed(ceed, CeedQFunctionContextSetData(blasius_context, CEED_MEM_HOST, CEED_USE_POINTER, sizeof(*blasius_ctx), blasius_ctx)); 347 PetscCallCeed(ceed, CeedQFunctionContextSetDataDestroy(blasius_context, CEED_MEM_HOST, FreeContextPetsc)); 348 349 PetscCallCeed(ceed, CeedQFunctionContextDestroy(&problem->ics.qfunction_context)); 350 problem->ics.qfunction_context = blasius_context; 351 if (use_stg) { 352 PetscCall(SetupStg(comm, dm, problem, user, weakT, S_infty.Y.temperature, S_infty.Y.pressure)); 353 } else if (diff_filter_mms) { 354 PetscCall(DifferentialFilterMmsICSetup(problem)); 355 } else { 356 PetscCheck((user->phys->state_var == STATEVAR_CONSERVATIVE) || (user->app_ctx->test_type == TESTTYPE_DIFF_FILTER), user->comm, 357 PETSC_ERR_ARG_INCOMP, "Can only use conservative variables with Blasius and weak inflow"); 358 problem->apply_inflow.qfunction = Blasius_Inflow; 359 problem->apply_inflow.qfunction_loc = Blasius_Inflow_loc; 360 problem->apply_inflow_jacobian.qfunction = Blasius_Inflow_Jacobian; 361 problem->apply_inflow_jacobian.qfunction_loc = Blasius_Inflow_Jacobian_loc; 362 PetscCallCeed(ceed, CeedQFunctionContextReferenceCopy(blasius_context, &problem->apply_inflow.qfunction_context)); 363 PetscCallCeed(ceed, CeedQFunctionContextReferenceCopy(blasius_context, &problem->apply_inflow_jacobian.qfunction_context)); 364 } 365 PetscFunctionReturn(PETSC_SUCCESS); 366 } 367