Introduction
Generation of synthetic turbulence at LES inlets can be defined using the cs_user_les_inflow_define user function, and possibly updated using cs_user_les_inflow_update, with cs_user_les_inflow_advanced allowing for finer definition of target statistics the inlet if needed.
Global caracteristics of synthetic turbulence inlets
General settings
The cs_user_les_inflow_define function is the main entry point for LES inflow definitions.
It can be used to set general options, such as the specific checkpoint/restart behavior, as in the following example:
false);
void cs_les_inflow_set_restart(bool allow_read, bool allow_write)
Define behavior of the LES inflow module in case of restart.
Definition: cs_les_inflow.c:2193
Defining inlet properties
For each LES inlet, the cs_les_inflow_add_inlet must be used.
For example, to use the Batten Method for boundary faces of a zone named INLET_1:
{
int n_entities = 50;
false,
n_entities,
0,
vel_r,
k_r,
eps_r);
}
const cs_zone_t * cs_boundary_zone_by_name(const char *name)
Return a pointer to a boundary zone based on its name if present.
Definition: cs_boundary_zone.c:711
double cs_real_t
Floating-point value.
Definition: cs_defs.h:319
void cs_les_inflow_add_inlet(cs_les_inflow_type_t type, bool volume_mode, const cs_zone_t *zone, int n_entities, int verbosity, const cs_real_t *vel_r, cs_real_t k_r, cs_real_t eps_r)
Add an inlet definition for synthetic turbulence inflow generation.
Definition: cs_les_inflow.c:650
@ CS_INFLOW_BATTEN
Definition: cs_les_inflow.h:60
And to use the Synthetic Eddy Method for boundary faces of a zone named INLET_2:
Modifying synthetic turbulence inlets
Updating base characteristics
To update reference velocity, turbulent kinetic energy, or dissipation rate for a given turbulence inlet, the cs_user_les_inflow_update function may be used. It is called automatically for each LES inlet defined previously.
The following example illustrates modifying values for the example zone named INLET_1:
if (strcmp(zone->name, "INLET_1") == 0) {
vel_r[0] = 19.0;
vel_r[1] = 0.0;
vel_r[2] = 0.0;
*k_r = 5.0;
*eps_r = 5.0;
}
Advanced LES inlet Example 1
Mean velocity, Reynolds stresses an dissipation are deduced from a wall law for the zone named INLET_1 (no modification of the statistics of the flow is provided for the other synthetic turbulence inlets).
if (strcmp(zone->name, "INLET_1") == 0) {
const cs_real_t yy = 1.0 - b_face_cog[f_id][1];
+ 7.8*(1. - exp(-
yplus/11.0)
+ (1.0 - exp(-
yplus/20.0)) *4.5
/ (1. + 4.0*
yplus/r_fro);
vel_l[i][0] = uplus * utau;
vel_l[i][1] = 0.0;
vel_l[i][2] = 0.0;
rij_l[i][3] = 0;
rij_l[i][4] = 0;
rij_l[i][5] = 0;
}
}
cs_real_t cs_real_3_t[3]
vector of 3 floating-point values
Definition: cs_defs.h:334
int cs_lnum_t
local mesh entity id
Definition: cs_defs.h:313
@ mu
Definition: cs_field_pointer.h:103
@ yplus
Definition: cs_field_pointer.h:239
#define CS_F_(e)
Macro used to return a field pointer by its enumerated value.
Definition: cs_field_pointer.h:51
static cs_real_t cs_math_pow2(cs_real_t x)
Compute the square of a real value.
Definition: cs_math.h:238
static cs_real_t cs_math_pow4(cs_real_t x)
Compute the 4-th power of a real value.
Definition: cs_math.h:270
cs_mesh_quantities_t * cs_glob_mesh_quantities
double cs_turb_xkappa
Definition: cs_turbulence_model.c:444
const cs_turb_ref_values_t * cs_glob_turb_ref_values
real(c_double), pointer, save uref
the characteristic flow velocity, used for the initialization of the turbulence. Negative value: not ...
Definition: cstphy.f90:353
double precision, dimension(ncharm), save kappa
Definition: cpincl.f90:96
cs_real_t * b_face_cog
Definition: cs_mesh_quantities.h:111
cs_lnum_t * b_face_cells
Definition: cs_mesh.h:112
double uref
Definition: cs_turbulence_model.h:169
Advanced LES Example 2
Reynolds stresses and dissipation at the inlet are computed using the turbulence intensity and standard laws for a circular pipe for for the zone named INLET_1 (no modification of the statistics of the flow is provided for the other synthetic turbulence inlets).
if (strcmp(zone->name, "INLET_1") == 0) {
vel_l[i][0] = 1.1;
vel_l[i][1] = 1.1;
vel_l[i][2] = 1.1;
x_ti,
x_hd,
&x_k,
&x_eps);
rij_l[i][0] = d2_s3 * x_k;
rij_l[i][1] = d2_s3 * x_k;
rij_l[i][2] = d2_s3 * x_k;
rij_l[i][3] = 0;
rij_l[i][4] = 0;
rij_l[i][5] = 0;
eps_l[i] = x_eps;
}
}
static cs_real_t cs_math_fmax(cs_real_t x, cs_real_t y)
Compute the max value of two real values.
Definition: cs_math.h:180
static cs_real_t cs_math_3_square_norm(const cs_real_t v[3])
Compute the square norm of a vector of 3 real values.
Definition: cs_math.h:456
void cs_turbulence_bc_ke_turb_intensity(double uref2, double t_intensity, double dh, double *k, double *eps)
Calculation of and from a diameter , a turbulent intensity and the reference velocity for a circu...
Definition: cs_turbulence_bc.c:827