11.1.9. Initial Condition¶

Each initial condition (IC) is specified over a rectangular region (or pie-shaped for cylindrical coordinates) that corresponds to the scalar numerical grid. These are 3D regions: X_w X_e, Y_s Y_n, and Z_t Z_b. The region is defined by the constant coordinates of each of the six faces, which may be specified as the physical coordinates or the cell indices. The physical coordinates are easier to specify than the cell indices. If cell sizes are not small enough to resolve a region specified using physical coordinates, MFIX will indicate this problem with an error message.

In cylindrical coordinates, when the theta direction crosses the 0 value, split that region into two regions: e.g., Split a region spanning 1.9 pi to 0.1 pi as 1.9 pi to 2 pi and 0 to 0.1 pi.

Initial condition regions may overlap. When an overlap occurs, MFIX uses the conditions specified for the higher IC number.

11.1.9.1. IC_X_W(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

X coordinate of the west face.

11.1.9.2. IC_X_E(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

X coordinate of the east face.

11.1.9.3. IC_Y_S(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Y coordinate of the south face.

11.1.9.4. IC_Y_N(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Y coordinate of the north face.

11.1.9.5. IC_Z_B(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Z coordinate of the bottom face.

11.1.9.6. IC_Z_T(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Z coordinate of the top face.

11.1.9.7. IC_I_W(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

I index of the west-most wall.

11.1.9.8. IC_I_E(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

I index of the east-most wall.

11.1.9.9. IC_J_S(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

J index of the south-most wall.

11.1.9.10. IC_J_N(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

J index of the north-most wall.

11.1.9.11. IC_K_B(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

K index of the bottom-most wall.

11.1.9.12. IC_K_T(IC)¶

Data Type: INTEGER

$1 \leq I C \leq 500$

K index of the top-most wall.

11.1.9.13. IC_TYPE(IC)¶

Data Type: CHARACTER

$1 \leq I C \leq 500$

Type of initial condition. Mainly used in restart runs to overwrite values read from the .RES file by specifying it as _PATCH_. The user needs to be careful when using the _PATCH_ option, since the values from the .RES file are overwritten and no error checking is done for the patched values.

11.1.9.14. IC_EP_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial void fraction in the IC region.

11.1.9.15. IC_P_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial gas pressure in the IC region. If this quantity is not specified, MFiX will set up a hydrostatic pressure profile, which varies only in the y-direction.

11.1.9.16. IC_P_STAR(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial solids pressure in the IC region. Usually, this value is specified as zero.

11.1.9.17. IC_L_SCALE(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Turbulence length scale in the IC region.

11.1.9.18. IC_ROP_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial bulk density (rop_s = ro_s x ep_s) of solids phase in the IC region. Users need to specify this IC only for polydisperse flow (MMAX > 1). Users must make sure that summation of ( IC_ROP_s(ic,m) / RO_s(m) ) over all solids phases is equal to ( 1.0 - IC_EP_g(ic)).

11.1.9.19. IC_EP_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial solids volume fraction of solids phase in the IC region. This may be specified in place of IC_ROP_s.

11.1.9.20. IC_PSD_TYPE(IC, PHASE)¶

Data Type: CHARACTER

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial particle size distribution type of solids phase in the IC region.

Table 11.49 Valid Values¶
Name	Default?	Description
`MONO`	◉	Uniform particle size.
`NORMAL`		Normal (Gaussian) particle size distribution.
`LOG_NORMAL`		Log-normal particle size distribution.
`CUSTOM`		Particle size distribution specified in external file.

11.1.9.21. IC_PSD_MEAN_DP(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial mean value of particle size distribution of solids phase in the IC region. For a log-normal psd, The mean diameter (µ) and standard deviation (𝜎) will be used to compute the log-normal parameters µ_ln and 𝜎_ln : µ_ln = ln(µ²/√(µ² + 𝜎²)) and 𝜎_ln = √(ln(1 + (𝜎/µ)²)))

11.1.9.22. IC_PSD_STDEV(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial standard deviation of particle size distribution of solids phase in the IC region. For a log-normal psd, The mean diameter (µ) and standard deviation (𝜎) will be used to compute the log-normal parameters µ_ln and 𝜎_ln : µ_ln = ln(µ²/√(µ² + 𝜎²)) and 𝜎_ln = √(ln(1 + (𝜎/µ)²)))

11.1.9.23. IC_PSD_MAX_DP(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial maximum particle size of particle size distribution of solids phase in the IC region.

11.1.9.24. IC_PSD_MIN_DP(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial minimum particle size of particle size distribution of solids phase in the IC region.

11.1.9.25. IC_T_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial gas phase temperature in the IC region.

11.1.9.26. IC_T_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial solids phase temperature in the IC region.

11.1.9.27. IC_THETA_M(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial solids phase granular temperature in the IC region.

11.1.9.28. IC_GAMA_RG(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Gas phase radiation coefficient in the IC region. Modify file rdtn2.inc to change the source term.

11.1.9.29. IC_T_RG(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Gas phase radiation temperature in the IC region.

11.1.9.30. IC_GAMA_RS(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Solids phase radiation coefficient in the IC region. Modify file energy_mod.f to change the source term.

11.1.9.31. IC_T_RS(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Solids phase radiation temperature in the IC region.

11.1.9.32. IC_U_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial x-component of gas velocity in the IC region.

11.1.9.33. IC_U_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial x-component of solids-phase velocity in the IC region.

11.1.9.34. IC_V_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial y-component of gas velocity in the IC region.

11.1.9.35. IC_V_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial y-component of solids-phase velocity in the IC region.

11.1.9.36. IC_W_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial z-component of gas velocity in the IC region.

11.1.9.37. IC_W_S(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial z-component of solids-phase velocity in the IC region.

11.1.9.38. IC_X_G(IC, SPECIES)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq S p e c i e s \leq 100$

Initial mass fraction of gas species.

11.1.9.39. IC_X_S(IC, PHASE, SPECIES)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$
$1 \leq S p e c i e s \leq 100$

Initial mass fraction of solids species.

11.1.9.40. IC_SCALAR(IC, SCALAR EQ.)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq S c a l a r E q . \leq 100$

Initial value of Scalar n, assigned to scalar equation.

11.1.9.41. IC_K_TURB_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial value of K in K-Epsilon equation.

11.1.9.42. IC_E_TURB_G(IC)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$

Initial value of Epsilon in K-Epsilon equation.

11.1.9.43. IC_DES_FIT_TO_REGION(IC)¶

Data Type: LOGICAL

$1 \leq I C \leq 500$

Flag for inflating initial lattice distribution: to the entire IC region.

11.1.9.44. IC_DES_LATTICE(IC, PHASE)¶

Data Type: CHARACTER

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Type of initial lattice distribution (simple cubic or hexagonal): to the entire IC region.

Table 11.50 Valid Values¶
Name	Default?	Description
`HEXA`	◉	Particles are distributed on a hexagonal close-packed lattice.
`CUBIC`		Particles are distributed on a cubical lattice.

11.1.9.45. IC_DES_SPACING(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Spacing between particle within initial lattice distribution: (expressed as a fraction of particle diameter) to the entire IC region.

11.1.9.46. IC_DES_SPACE_FACTOR_X(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Spacing factor in x-direction (multiplier of IC_DES_SPACING).

11.1.9.47. IC_DES_SPACE_FACTOR_Y(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Spacing factor in y-direction (multiplier of IC_DES_SPACING).

11.1.9.48. IC_DES_SPACE_FACTOR_Z(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Spacing factor in z-direction (multiplier of IC_DES_SPACING).

11.1.9.49. IC_DES_RAND(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Random factor applied to particle positions within the lattice distribution.

11.1.9.50. IC_DES_RAND_FACTOR_X(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Random factor in x-direction (multiplier of IC_DES_RAND)

11.1.9.51. IC_DES_RAND_FACTOR_Y(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Random factor in y-direction (multiplier of IC_DES_RAND)

11.1.9.52. IC_DES_RAND_FACTOR_Z(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Random factor in z-direction (multiplier of IC_DES_RAND)

11.1.9.53. IC_DES_SM(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial solids mass within the entire IC region.

11.1.9.54. IC_DES_NP(IC, PHASE)¶

Data Type: INTEGER

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initial particle count within the entire IC region.

11.1.9.55. IC_DES_CHECK_STL_OVERLAP(IC, PHASE)¶

Data Type: LOGICAL

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Check for particle overlap with SL geometry: in the entire IC region.

11.1.9.56. IC_PIC_CONST_STATWT(IC, PHASE)¶

Data Type: DOUBLE PRECISION

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Flag to specify the initial constant statistical: weight for computational particles/parcels. Actual number of parcels will be automatically computed.

11.1.9.57. IC_SQP_RANDOM_Q(IC, PHASE)¶

Data Type: LOGICAL

$1 \leq I C \leq 500$
$1 \leq P h a s e \leq 10$

Initialize SQP with random orientation (quaternion) in the IC region.