xref: /honee/qfunctions/blasius.h (revision 224fc8c867bfdf53209e49be2150ec3eb3d75900)
1 // SPDX-FileCopyrightText: Copyright (c) 2017-2024, HONEE contributors.
2 // SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause
3 
4 /// @file
5 /// Operator for HONEE
6 #include <ceed/types.h>
7 
8 #include "newtonian_state.h"
9 #include "newtonian_types.h"
10 #include "utils.h"
11 
12 #define BLASIUS_MAX_N_CHEBYSHEV 50
13 
14 typedef struct BlasiusContext_ *BlasiusContext;
15 struct BlasiusContext_ {
16   bool                             implicit;  // !< Using implicit timesteping or not
17   bool                             weakT;     // !< flag to set Temperature weakly at inflow
18   CeedScalar                       delta0;    // !< Boundary layer height at inflow
19   State                            S_infty;
20   CeedScalar                       T_wall;                                // !< Temperature at the wall
21   CeedScalar                       x_inflow;                              // !< Location of inflow in x
22   CeedScalar                       n_cheb;                                // !< Number of Chebyshev terms
23   CeedScalar                      *X;                                     // !< Chebyshev polynomial coordinate vector (CPU only)
24   CeedScalar                       eta_max;                               // !< Maximum eta in the domain
25   CeedScalar                       Tf_cheb[BLASIUS_MAX_N_CHEBYSHEV];      // !< Chebyshev coefficient for f
26   CeedScalar                       Th_cheb[BLASIUS_MAX_N_CHEBYSHEV - 1];  // !< Chebyshev coefficient for h
27   struct NewtonianIdealGasContext_ newtonian_ctx;
28 };
29 
30 // *****************************************************************************
31 // This helper function evaluates Chebyshev polynomials with a set of coefficients with all their derivatives represented as a recurrence table.
32 // *****************************************************************************
33 CEED_QFUNCTION_HELPER void ChebyshevEval(int N, const double *Tf, double x, double eta_max, double *f) {
34   double dX_deta = 2 / eta_max;
35   // Chebyshev polynomials T_0, T_1, T_2 of the first kind in (-1,1)
36   double table[4][3] = {
37       {1, x, 2 * x * x - 1},
38       {0, 1, 4 * x        },
39       {0, 0, 4            },
40       {0, 0, 0            }
41   };
42   for (int i = 0; i < 4; i++) {
43     // i-th derivative of f
44     f[i] = table[i][0] * Tf[0] + table[i][1] * Tf[1] + table[i][2] * Tf[2];
45   }
46   for (int i = 3; i < N; i++) {
47     // T_n(x) = 2xT_{n-1}(x) - T_{n-2}(x)
48     table[0][i % 3] = 2 * x * table[0][(i - 1) % 3] - table[0][(i - 2) % 3];
49     // Differentiate Chebyshev polynomials with the recurrence relation
50     for (int j = 1; j < 4; j++) {
51       // T'_{n}(x)/n = 2T_{n-1}(x) + T'_{n-2}(x)/n-2
52       table[j][i % 3] = i * (2 * table[j - 1][(i - 1) % 3] + table[j][(i - 2) % 3] / (i - 2));
53     }
54     for (int j = 0; j < 4; j++) {
55       f[j] += table[j][i % 3] * Tf[i];
56     }
57   }
58   for (int i = 1; i < 4; i++) {
59     // Transform derivatives from Chebyshev [-1, 1] to [0, eta_max].
60     for (int j = 0; j < i; j++) f[i] *= dX_deta;
61   }
62 }
63 
64 // *****************************************************************************
65 // This helper function computes the Blasius boundary layer solution.
66 // *****************************************************************************
67 State CEED_QFUNCTION_HELPER(BlasiusSolution)(const BlasiusContext blasius, const CeedScalar x[3], const CeedScalar x0, const CeedScalar x_inflow,
68                                              const CeedScalar rho_infty, CeedScalar *t12) {
69   CeedInt    N       = blasius->n_cheb;
70   CeedScalar mu      = blasius->newtonian_ctx.mu;
71   State      S_infty = blasius->S_infty;
72   CeedScalar nu      = mu / rho_infty;
73   CeedScalar U_infty = Norm3(S_infty.Y.velocity);
74   CeedScalar eta     = x[1] * sqrt(U_infty / (nu * (x0 + x[0] - x_inflow)));
75   CeedScalar X       = 2 * (eta / blasius->eta_max) - 1.;
76   CeedScalar Rd      = GasConstant(&blasius->newtonian_ctx);
77 
78   CeedScalar f[4], h[4];
79   ChebyshevEval(N, blasius->Tf_cheb, X, blasius->eta_max, f);
80   ChebyshevEval(N - 1, blasius->Th_cheb, X, blasius->eta_max, h);
81 
82   *t12 = mu * U_infty * f[2] * sqrt(U_infty / (nu * (x0 + x[0] - x_inflow)));
83 
84   CeedScalar Y[5];
85   Y[1] = U_infty * f[1];
86   Y[2] = 0.5 * sqrt(nu * U_infty / (x0 + x[0] - x_inflow)) * (eta * f[1] - f[0]);
87   Y[3] = 0.;
88   Y[4] = S_infty.Y.temperature * h[0];
89   Y[0] = rho_infty / h[0] * Rd * Y[4];
90   return StateFromY(&blasius->newtonian_ctx, Y);
91 }
92 
93 // *****************************************************************************
94 // This QFunction sets a Blasius boundary layer for the initial condition
95 // *****************************************************************************
96 CEED_QFUNCTION(ICsBlasius)(void *ctx, CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
97   const CeedScalar(*X)[CEED_Q_VLA] = (const CeedScalar(*)[CEED_Q_VLA])in[0];
98   CeedScalar(*q0)[CEED_Q_VLA]      = (CeedScalar(*)[CEED_Q_VLA])out[0];
99 
100   const BlasiusContext           context  = (BlasiusContext)ctx;
101   const NewtonianIdealGasContext gas      = &context->newtonian_ctx;
102   const CeedScalar               mu       = context->newtonian_ctx.mu;
103   const CeedScalar               delta0   = context->delta0;
104   const CeedScalar               x_inflow = context->x_inflow;
105   CeedScalar                     t12;
106 
107   const State      S_infty = context->S_infty;
108   const CeedScalar U_infty = Norm3(S_infty.Y.velocity);
109 
110   const CeedScalar x0 = U_infty * S_infty.U.density / (mu * 25 / Square(delta0));
111 
112   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
113     const CeedScalar x[3] = {X[0][i], X[1][i], X[2][i]};
114     State            s    = BlasiusSolution(context, x, x0, x_inflow, S_infty.U.density, &t12);
115     CeedScalar       q[5];
116 
117     StateToQ(gas, s, q, gas->state_var);
118     for (CeedInt j = 0; j < 5; j++) q0[j][i] = q[j];
119   }
120   return 0;
121 }
122 
123 // *****************************************************************************
124 CEED_QFUNCTION(Blasius_Inflow)(void *ctx, CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
125   const BlasiusContext context     = (BlasiusContext)ctx;
126   const CeedScalar(*q)[CEED_Q_VLA] = (const CeedScalar(*)[CEED_Q_VLA])in[0];
127   const CeedScalar(*q_data_sur)    = in[2];
128   const CeedScalar(*X)[CEED_Q_VLA] = (const CeedScalar(*)[CEED_Q_VLA])in[3];
129   CeedScalar(*v)[CEED_Q_VLA]       = (CeedScalar(*)[CEED_Q_VLA])out[0];
130   CeedScalar(*jac_data_sur)        = context->newtonian_ctx.is_implicit ? out[1] : NULL;
131 
132   const bool                     is_implicit = context->implicit;
133   const NewtonianIdealGasContext gas         = &context->newtonian_ctx;
134   State                          S_infty     = context->S_infty;
135   const CeedScalar               rho_0       = S_infty.U.density;
136   const CeedScalar               U_infty     = Norm3(S_infty.Y.velocity);
137   const CeedScalar               x0          = U_infty * rho_0 / (gas->mu * 25 / Square(context->delta0));
138   const CeedScalar               zeros[11]   = {0.};
139 
140   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
141     CeedScalar wdetJb, normal[3];
142     QdataBoundaryUnpack_3D(Q, i, q_data_sur, &wdetJb, NULL, normal);
143     wdetJb *= is_implicit ? -1. : 1.;
144 
145     // Calculate inflow values
146     const CeedScalar x[3] = {X[0][i], X[1][i], 0.};
147     CeedScalar       t12;
148     State            s = BlasiusSolution(context, x, x0, context->x_inflow, rho_0, &t12);
149     CeedScalar       qi[5];
150     for (CeedInt j = 0; j < 5; j++) qi[j] = q[j][i];
151     State s_int = StateFromU(gas, qi);
152 
153     // enabling user to choose between weak T and weak rho inflow
154     if (context->weakT) {  // density from the current solution
155       s.U.density = s_int.U.density;
156       s.Y         = StatePrimitiveFromConservative(gas, s.U);
157     } else {  // Total energy from current solution
158       s.U.E_total = s_int.U.E_total;
159       s.Y         = StatePrimitiveFromConservative(gas, s.U);
160     }
161 
162     StateConservative Flux_inviscid[3];
163     FluxInviscid(&context->newtonian_ctx, s, Flux_inviscid);
164 
165     const CeedScalar stress[3][3] = {
166         {0,   t12, 0},
167         {t12, 0,   0},
168         {0,   0,   0}
169     };
170     const CeedScalar Fe[3] = {0};  // TODO: viscous energy flux needs grad temperature
171     CeedScalar       Flux[5];
172     FluxTotal_Boundary(Flux_inviscid, stress, Fe, normal, Flux);
173     for (CeedInt j = 0; j < 5; j++) v[j][i] = -wdetJb * Flux[j];
174     if (is_implicit) StoredValuesPack(Q, i, 0, 11, zeros, jac_data_sur);
175   }
176   return 0;
177 }
178 
179 // *****************************************************************************
180 CEED_QFUNCTION(Blasius_Inflow_Jacobian)(void *ctx, CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
181   const CeedScalar(*dq)[CEED_Q_VLA] = (const CeedScalar(*)[CEED_Q_VLA])in[0];
182   const CeedScalar(*q_data_sur)     = in[2];
183   const CeedScalar(*X)[CEED_Q_VLA]  = (const CeedScalar(*)[CEED_Q_VLA])in[3];
184   CeedScalar(*v)[CEED_Q_VLA]        = (CeedScalar(*)[CEED_Q_VLA])out[0];
185 
186   const BlasiusContext           context     = (BlasiusContext)ctx;
187   const NewtonianIdealGasContext gas         = &context->newtonian_ctx;
188   const bool                     is_implicit = context->implicit;
189   const CeedScalar               Rd          = GasConstant(gas);
190   const CeedScalar               gamma       = HeatCapacityRatio(gas);
191   const State                    S_infty     = context->S_infty;
192   const CeedScalar               rho_0       = S_infty.U.density;
193   const CeedScalar               U_infty     = Norm3(S_infty.Y.velocity);
194   const CeedScalar               x0          = U_infty * rho_0 / (gas->mu * 25 / Square(context->delta0));
195 
196   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
197     CeedScalar wdetJb, normal[3];
198     QdataBoundaryUnpack_3D(Q, i, q_data_sur, &wdetJb, NULL, normal);
199     wdetJb *= is_implicit ? -1. : 1.;
200 
201     // Calculate inflow values
202     const CeedScalar x[3] = {X[0][i], X[1][i], X[2][i]};
203     CeedScalar       t12;
204     State            s = BlasiusSolution(context, x, x0, 0, rho_0, &t12);
205 
206     // enabling user to choose between weak T and weak rho inflow
207     CeedScalar drho, dE, dP;
208     if (context->weakT) {
209       // rho should be from the current solution
210       drho                   = dq[0][i];
211       CeedScalar dE_internal = drho * gas->cv * S_infty.Y.temperature;
212       CeedScalar dE_kinetic  = .5 * drho * Dot3(s.Y.velocity, s.Y.velocity);
213       dE                     = dE_internal + dE_kinetic;
214       dP                     = drho * Rd * S_infty.Y.temperature;  // interior rho with exterior T
215     } else {
216       // rho specified, E_internal from solution
217       drho = 0;
218       dE   = dq[4][i];
219       dP   = dE * (gamma - 1.);
220     }
221 
222     const CeedScalar u_normal = Dot3(normal, s.Y.velocity);
223 
224     v[0][i] = -wdetJb * drho * u_normal;
225     for (int j = 0; j < 3; j++) {
226       v[j + 1][i] = -wdetJb * (drho * u_normal * s.Y.velocity[j] + normal[j] * dP);
227     }
228     v[4][i] = -wdetJb * u_normal * (dE + dP);
229   }
230   return 0;
231 }
232