UDF †

  • UDF is a text file. One can browse and edit it using a text editor, but it.can be more easily handled with "Gourmet". See the manuals below for general information on UDF.
    • English: &ref(): File not found: "udf_spec_eng.pdf" at page "UdfFile";
    • Japanese: &ref(): File not found: "UDF_Spec_jpn.pdf" at page "UdfFile";
  • In the case of UDF used for KAPSEL, one must first choose the type of problem you want to simulate by selecting "constitutive_eq" from list below.
    • Navier_Stokes: (sedimentation, diffusion, coagulation)
    • Shear_Navier_Stokes: (rheology, chain in shear flow)
    • Electrolyte: (electrophoresis)
↑

List of variables in UDF for KAPSEL (input.udf) †

constitutive_eq: type: {Navier_Stokes, Shear_Navier_Stokes, Electrolyte}

Navier_Stokes

  • DX: Girid width (this is the unit of length)
  • RHO: Density of fluid
  • ETA: Viscosity of fluid
  • kBT: Temperature of dispersion
  • alpha_v: Scaling factor for fluctuating force (translation)
  • alpha_o: Scaling factor for fluctuating torque (rotation)

Shear_Navier_Stokes

  • DX: Girid width (this is the unit of length)
  • RHO: Density of fluid
  • ETA: Viscosity of fluid
  • kBT: Temperature of dispersion
  • alpha_v: Scaling factor for fluctuating force (translation)
  • alpha_o: Scaling factor for fluctuating torque (rotation)
  • External_field: type: {DC, AC}: Steady shear (DC) or Oscillatory shear (AC)
DC
  • shear_rate: Shear rate (DC)
AC
  • shear_rate: Max shear rate (AC)

Electrolyte

  • DX: Girid width (this is the unit of length)
  • RHO: Density of fluid
  • ETA: Viscosity of fluid
  • kBT: Temperature of dispersion
  • Dielectric_cst: Dielectric constant of fluid
  • INIT_profile: Uniform: use uniform ionic densities as an initial state. Poisson_Boltzmann: use optimal ionic densities as an initial state by solving Poisson-Boltzman Eq. for a given initial particle configuration in advance to start simulation.
  • Add_salt: type: salt: salt is added, saltfree: no salt is added
salt
  • Valency_positive_ion: Valency of positive ions
  • Valency_negative_ion: Valency of negative ions
  • Onsager_coeff_positive_ion: Onsager transport coefficient of positive ions
  • Onsager_coeff_negative_ion: Onsager transport coefficient of negative ions
  • Debye_length: Debye screening length This causes the corresponding salt concentration to be specified automatically.
saltfree
  • Valency_counterion: Valency of counter ions
  • Onsager_coeff_counterion: {Onsager transport coefficient of counter ions
  • Electric_field: type: ON: apply external electric field, OFF: no external electric field
    • ON: type: DC: apply steady electric field, AC: apply oscillatory electric field
    DC
    • Ex: Intensity of the x-direction electric field
    • Ey: Intensity of the y-direction electric field
    • Ez: Intensity of the z-direction electric field
    AC
    • Ex: Max intensity of the x-direction electric field
    • Ey: Max intensity of the y-direction electric field
    • Ez: Max intensity of the z-direction electric field
    • Frequency: Frequency of an oscillatory electric field.

object_type: type: {spherical_particle, chain}

spherical_particle

  • Particle_spec[]
    • Particle_spec[0]: (0 means the 1st component)
      • Particle_number: Number of particles
      • MASS_RATIO: Density of particle / density of fluid
      • Surface_charge: Valency of particles (total charge carried by a single particle in unit of electron charge)

chain

  • Chain_spec[]
    • Chain_spec[0] (0 meand the 1st component)
      • Beads_number: Number of beads in a single chain
      • Chain_number: Number of chains in a simulation box
      • MASS_RATIO: Density of beads / density of fluid
      • Surface_charge: Valency of beads (total charge carried by a single bead in unit of electron charge)

A_XI: Thickness of the particle-fluid boundary

A: Radius pd particles or beads

gravity

  • G: Gravitational acceleration
  • G_direction: -X , -Y , -Z: the direction in which gravity is applied

EPSILON: &color(foreground[,background]){text};

LJ_powers: {12:6, 24:12, 36:18}: &color(foreground[,background]){text};

mesh

  • NPX: &color(foreground[,background]){text};
  • NPY: &color(foreground[,background]){text};
  • NPZ: &color(foreground[,background]){text};

time_increment: type: {auto, manual}: &color(foreground[,background]){text};

auto

  • factor: &color(foreground[,background]){text};

manual

  • delta_t: &color(foreground[,background]){text};

switch

  • ROTATION: {ON, OFF}: &color(foreground[,background]){text};
  • HYDRO_int: {Correct, free draining, squeeze-lubrication and drain}
  • Stokes: {with advection, w/o advection}
  • LJ_truncate: {ON, OFF, NONE}
  • INIT_distribution: type: {uniform_random, random_walk, FCC, BCC, user_specify}
random_walk
  • iteration
user_specify
  • Particles[]
    • Particles[0] 
      - R
  - x: 
  - y: 
  - z: 
- v
  - x: 
  - y: 
  - z:
FIX_CELL
  • x: {ON, OFF}
  • y: {ON, OFF}
  • z: {ON, OFF}

boundary_condition: type: {z_dirichlet, full_periodic}

z_dirichlet

  • wall_velocity_x:
  • wall_velocity_y:
  • wall_velocity_z:

output

  • GTS:
  • Num_snap:
  • AVS: {ON, OFF}
ON
  • Out_dir:
  • Out_name:
  • File_Type: {BINARY, ASCII}
  • UDF: {ON, OFF}

E:

t:

Particles[]

  • Particles[] 
    - R
  - x: 
  - y: 
  - z: 
- v
 - x: 
 - y: 
 - z:

resume

  • Calculation: {NEW, CONTINUE}