tFirst try at a more appropriate time step when coupling the fluid and transient solvers. - cngf-pf - continuum model for granular flows with pore-pressure dynamics (renamed from 1d_fd_simple_shear)
(HTM) git clone git://src.adamsgaard.dk/cngf-pf
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---
(DIR) commit cc5fef7b04e30a4b6c1d41c4e3d47dddd2e45173
(DIR) parent a91a9d97e214821989e66263c3de85574dc6871e
(HTM) Author: Ian Madden <iamadden@stanford.edu>
Date: Thu, 11 Feb 2021 09:41:27 -0800
First try at a more appropriate time step when coupling the fluid and transient solvers.
Signed-off-by: Anders Damsgaard <anders@adamsgaard.dk>
Diffstat:
M cngf-pf.c | 5 +++++
M simulation.c | 24 +++++++++++++++++++++++-
M simulation.h | 2 ++
3 files changed, 30 insertions(+), 1 deletion(-)
---
(DIR) diff --git a/cngf-pf.c b/cngf-pf.c
t@@ -254,8 +254,13 @@ main(int argc, char *argv[])
free_arrays(&sim);
return 20;
}
+ if (sim.transient) {
+ set_coupled_fluid_transient_timestep(&sim, 0.5);
+ }
}
}
+ fprintf(stderr, "t_val = %g \n", sim.dt);
+
if (sim.dt > sim.file_dt)
sim.dt = sim.file_dt;
(DIR) diff --git a/simulation.c b/simulation.c
t@@ -834,6 +834,7 @@ coupled_shear_solver(struct simulation *sim,
printf("sim->mu[%d] = %g\n", i, sim->mu[i]);
}
#endif
+
/* stable porosity change field == coupled solution converged */
if (sim->transient) {
for (i = 0; i < sim->nz; ++i)
t@@ -852,7 +853,6 @@ coupled_shear_solver(struct simulation *sim,
}
}
} while (sim->transient);
-
if (!isnan(sim->v_x_limit) || !isnan(sim->v_x_fix)) {
if (!isnan(sim->v_x_limit)) {
vel_res_norm = (sim->v_x_limit - sim->v_x[sim->nz - 1])
t@@ -895,3 +895,25 @@ find_flux(const struct simulation *sim)
return flux;
}
+
+int set_coupled_fluid_transient_timestep(struct simulation *sim, const double safety) {
+ // Compute Maximum Strain Rate Expected
+ double max_gamma_dot = 1/sim->d;
+ if (!isnan(sim->v_x_fix)) max_gamma_dot = sim->v_x_fix / sim->dz;
+ if (!isnan(sim->v_x_limit)) max_gamma_dot = sim->v_x_limit / sim->dz;
+ // Compute estimate for mu for cooperativity length
+ double mu = (sim->mu_wall / ((sim->sigma_n[sim->nz-1]- sim->p_f_mod_ampl)/ (sim->P_wall - sim->p_f_top))) + sim->dilatancy_constant * sim->phi[sim->nz-1];
+ // Compute estimate for cooperativity length
+ double xi = cooperativity_length(sim->A,
+ sim->d,
+ mu,
+ (sim->sigma_n[sim->nz-1]- sim->p_f_mod_ampl),
+ sim->mu_s,
+ sim->C);
+ // Compute Maximum Expected Inertia Number
+ double max_I = max_gamma_dot * sim->d / sqrt((sim->sigma_n[sim->nz-1]- sim->p_f_mod_ampl) / sim->rho_s);
+ double t_val = xi *(sim->alpha + sim->phi[sim->nz-1]*sim->beta_f) * sim->mu_f
+ / (sim->phi[sim->nz-1] * sim->phi[sim->nz-1]* sim->phi[sim->nz-1]*sim->L_z* max_I);
+ if (sim->dt > safety * t_val) sim->dt = safety * t_val;
+ return 0;
+}
(DIR) diff --git a/simulation.h b/simulation.h
t@@ -153,6 +153,8 @@ void print_output(struct simulation *sim, FILE *fp, const int normalize);
int coupled_shear_solver(struct simulation *sim,
const int max_iter,
const double rel_tol);
+
+int set_coupled_fluid_transient_timestep(struct simulation *sim, const double safety);
double find_flux(const struct simulation *sim);