Color model – Image Sequence Protocol

The image sequence protocol is designed to perform a set steady-state simulations based on a sequence of 3D (8-bit) images provided by the user. The images might be the output of a previous LBPM simulation, a sequence of (segmented) experimental data, or data generated from a custom routine. The image sequence protocol will apply the same set of flow conditions to all images in the sequence. This means

• the image labels and any associated properties are the same

• the external boundary conditions are the same

• the physical simulation parameters are the same

The image sequence protocol does not set boundary conditions by default. It is up to the user to determine the flow condition, with the understanding that the same set of will be applied to each image in the sequence.

To enable the image sequence protocol, the following keys should be set within the Color section of the input database

Color {
   protocol = "image sequence"
   image_sequence = "Bentheimer_LB_RelPerm_intermediate_oil_wet_Sw_0p37.raw", "Bentheimer_LB_RelPerm_intermediate_oil_wet_Sw_0p72.raw"
                                      // comma separated list of image names
   capillary_number = 1e-4            // capillary number for the displacement
   timestepMax = 1000000              // maximum timtestep
   alpha = 0.005                      // controls interfacial tension
   rhoA = 1.0                         // controls the density of fluid A
   rhoB = 1.0                         // controls the density of fluid B
   tauA = 0.7                         // controls the viscosity of fluid A
   tauB = 0.7                         // controls the viscosity of fluid B
   F = 0, 0, 0                        // body force
   WettingConvention = "SCAL"         // convention for sign of wetting affinity
   ComponentLabels = 0, -1, -2        // image labels for solid voxels
   ComponentAffinity = 1.0, 1.0, 0.6  // controls the wetting affinity for each label
   Restart = false
}
Domain {
   Filename = "Bentheimer_LB_RelPerm_intermediate_oil_wet_Sw_0p37.raw"
   ReadType = "8bit"              // data type
   N = 900, 900, 1600             // size of original image
   nproc = 2, 2, 2                // process grid
   n = 200, 200, 200              // sub-domain size
   offset = 300, 300, 300         // offset to read sub-domain
   voxel_length = 1.66            // voxel length (in microns)
   ReadValues = -2, -1, 0, 1, 2   // labels within the original image
   WriteValues = -2, -1, 0, 1, 2  // associated labels to be used by LBPM
   BC = 0                         // boundary condition type (0 for periodic)
}
Analysis {
   analysis_interval = 1000           // logging interval for timelog.csv
   subphase_analysis_interval = 5000  // loggging interval for subphase.csv
   visualization_interval = 100000    // interval to write visualization files
   N_threads = 4                      // number of analysis threads (GPU version only)
   restart_interval = 1000000         // interval to write restart file
   restart_file = "Restart"           // base name of restart file
}
Visualization {
   write_silo = true     // write SILO databases with assigned variables
   save_8bit_raw = true  // write labeled 8-bit binary files with phase assignments
   save_phase_field = true  // save phase field within SILO database
   save_pressure = false    // save pressure field within SILO database
   save_velocity = false    // save velocity field within SILO database
}
FlowAdaptor {
   min_steady_timesteps = 100000     // minimum number of timesteps per steady point
   max_steady_timesteps = 250000     // maximum number of timesteps per steady point
}