8.7 Initial Conditions
8.7.2 Description
Water column initial conditions are recommended for each simulated sediment fraction. Supported initial condition model implementations are the same as those presented in Section 7.10.2 and are summarised for sediment in Table 8.4. The corresponding sediment initial condition commands are summarised in Table 8.5.
Extensions of each implementation for sediment are described below. Initial bed composition is specified within the Sediment Control File.
| Model Implementation | Description |
|---|---|
| Spatially Constant | Sets initial conditions using spatially constant fields in 2D or as horizontal uniform profiles in 3D. |
| Spatially Varying | Sets initial constituent values using 2D or 3D cell based CSV inputs. |
| Restart File | Reads initial conditions from a previous simulation restart file. |
| Command | Description |
|---|---|
| Initial Sediment Concentration | Optional - Sets a spatially constant suspended sediment concentration for each simulated sediment fraction. This value is also constant for all water depths. |
| Initial Scalar Profile | Optional - Used to assign spatially constant but depth varying 3D initial condition profiles. |
| Initial Condition 2D | Optional - Used to specify spatially varying depth averaged initial suspended sediment fields. |
| Initial Condition 3D | Optional - Used to specify spatially varying 3D initial suspended sediment fields. |
| Restart File | Optional - Used to initialise suspended sediment fields from a prior simulation. |
8.7.3 Spatially Constant
8.7.3.1 Two Dimensional
This method sets a single value across the entire model domain for each simulated sediment fraction.
If multiple sediment fractions are simulated, initial concentrations are specified as comma separated values.
8.7.3.2 Three Dimensional
This method sets a single horizontally constant value for each vertical layer across the entire model domain for each simulated sediment fraction using the
To set tracer, salinity, temperature and two sediment fraction initial conditions as a laterally uniform profile, the referenced csv file requires the following columns:
- DEPTH: Depth values (m) from the surface downwards (positive downward) for assigning concentrations
- SAL: Corresponding salinity (psu) values at each of the depths in the DEPTH column
- TEMP: Corresponding temperatures (C) at each of the depths in the DEPTH column
- TRACE_1: Corresponding tracer 1 concentrations (g/m\(^3\)) at each of the depths in the DEPTH column
- SED_1: Corresponding sediment fraction 1 concentrations (g/m\(^3\)) at each of the depths in the DEPTH column
- SED_2: Corresponding sediment fraction 2 concentrations (g/m\(^3\)) at each of the depths in the DEPTH column
Example initial scalar profile CSV.
IC_Profile_011.csv
DEPTH, SAL, TEMP, TRACE_1, SED_1, SED_2
0.0, 35.0, 25.0, 12.0, 100.0, 23.0
5.0, 35.0, 18.0, 12.0, 100.0, 25.0
10.0, 35.0, 11.0, 20.0, 150.0, 50.0
8.7.4 Spatially Varying
8.7.4.1 Two Dimensional
Initial conditions can be set as spatial varying (depth averaged) across the model domain for sediment concentrations within a 2D model with the
This command was previously described in Section 5.15.4. To set salinity, temperature, tracer and two sediment initial conditions, the referenced csv file requires a column for each as follows.
- ‘SAL’ (psu) for salinity
- ‘TEMP’ (C) for temperature
- ‘TRACE_1’ (g/m\(^3\)) for tracers
- ‘SED_1’ (g/m\(^3\)) for sediment fraction 1
- ‘SED_2’ (g/m\(^3\)) for sediment fraction 2
Not all 2D cell IDs need be included in the csv file, so if this command is issued after any of the three commands listed in Section 8.7.3 then this Initial Condition 2D will overwrite only those cells specified. This command can be issued in either 2D or 3D simulations.
Example initial condition 2D file.
IC_Midnight_Lake_2D_011.csv - This lake resides over six TUFLOW FV cells
ID, WL, U, V, SAL, TEMP, TRACE_1, SED_1, SED_2
23, 1.1, 0.0, 0.0, 1.6, 20.0, 50.0, 10.0, 37.0
28, 1.1, 0.0, 0.0, 2.3, 20.0, 60.0, 10.0, 37.0
29, 1.1, 0.0, 0.0, 1.8, 20.0, 70.0, 11.0, 38.0
42, 1.1, 0.0, 0.0, 1.2, 20.0, 80.0, 10.0, 37.0
45, 1.1, 0.0, 0.0, 2.4, 25.0, 90.0, 10.0, 37.0
46, 1.1, 0.0, 0.0, 2.3, 20.0, 95.0, 20.0, 57.08.7.4.2 Three Dimensional
Initial conditions can be set at every three dimensional cell across the model domain for sediment concentrations within a 3D model (only) with the
This command was previously described in Section 6.8.3. To set salinity, temperature, tracer and one sediment fraction initial conditions, the referenced csv file requires a column for each as follows.
- ‘SAL’ (psu) for salinity
- ‘TEMP’ (C) for temperature
- ‘TRACE_1’ (g/m\(^3\)) for tracers
- ‘SED_1’ (g/m\(^3\)) for sediment fraction 1
Not all 3D cell IDs need be included in the csv file, so if this command is issued after any of the three commands listed in Section 8.7.3 then this Initial Condition 3D will overwrite only those cells specified. This command can only be issued in 3D simulations.
IC_ML_3D_037.csv - This lake resides over 18 3D cells (6 2D cells x 3 layers deep)
ID, WL, U, V, SAL, TEMP, TRACE_1, SED_1
69, 1.1, 0.0, 0.0, 0.0, 1.20, 20.0, 37.0
70, 1.1, 0.0, 0.0, 0.0, 1.28, 22.0, 37.0
71, 1.1, 0.0, 0.0, 0.0, 1.35, 24.0, 37.0
84, 1.1, 0.0, 0.0, 0.0, 1.42, 26.0, 37.0
85, 1.1, 0.0, 0.0, 0.0, 1.48, 28.0, 37.0
86, 1.1, 0.0, 0.0, 0.0, 1.55, 30.0, 37.0
87, 1.1, 0.0, 0.0, 0.0, 1.63, 32.0, 17.0
88, 1.1, 0.0, 0.0, 0.0, 1.70, 34.0, 37.0
89, 1.1, 0.0, 0.0, 0.0, 1.77, 36.0, 17.0
126, 1.1, 0.0, 0.0, 0.0, 1.84, 38.0, 27.0
127, 1.1, 0.0, 0.0, 0.0, 1.90, 40.0, 37.0
128, 1.1, 0.0, 0.0, 0.0, 1.97, 42.0, 37.0
135, 1.1, 0.0, 0.0, 0.0, 2.05, 44.0, 37.0
136, 1.1, 0.0, 0.0, 0.0, 2.12, 47.0, 44.0
137, 1.1, 0.0, 0.0, 0.0, 2.20, 49.0, 37.0
198, 1.1, 0.0, 0.0, 0.0, 2.28, 52.0, 37.0
199, 1.1, 0.0, 0.0, 0.0, 2.38, 55.0, 37.0
200, 1.1, 0.0, 0.0, 0.0, 2.50, 60.0, 37.08.7.5 Restart File
Restart files can be used to provide initial conditions for sediment concentrations in the same manner as described in Section 5.15.5. The combination of sediments (and other variables) must be the same in the restart file and restarted simulation. Sediment properties specified in the sediment control file may change between simulations.
This restart file should be used in combination with the bed restart file option specified in the sediment control file to ensure consistency between water column and bed initial conditions.