5.15 Initial Conditions
5.15.1 Command Status
Optional - If no initial conditions are user specified TUFLOW FV will automatically set the initial water level at each cell to the maximum of the bathymetry level, or datum level 0.0 (m or ft). Velocities are set to a default value of 0.0 (m/s or ft/s).
5.15.2 Description
Initial conditions set the starting state values of every cell within the model. Initial conditions can be specified as spatially constant or varying, and a restart file created from a previous model run can be deployed. Supported initial condition model implementations are summarised in Table 5.28, with links to the relevant implementation sections below. Initial condition commands for the 2D HD simulation class are provided in Table 5.29.
Initial condition and restart commands adhere to the command layering approach, akin to that described in Section 5.13.3.1.
| Model Implementation | Description |
|---|---|
| Spatially Constant | Domain wide constant initial conditions. |
| Spatially Varying | Spatially varying initial conditions from input files. |
| Restart File | Initialise from an existing restart file. |
| Command | Description |
|---|---|
| Initial Water Level | Optional - Sets the initial water level to a global user specified value. |
| Initial Condition 2D | Optional - File path to initial condition 2d csv file. Allows for user specified spatially varying water level and velocity initial conditions. |
| RestartFile | Optional - Load the simulation initial conditions from a restart file (.rst) generated by a previous TUFLOW FV simulation. |
| Use Restart File Time | Optional - Switch to choose whether to use the timestamp written to the restart file (.rst) or to use the simulation start time. |
5.15.3 Spatially Constant
This implementation type is used to set a constant
5.15.4 Spatially Varying
This initial condition implementation uses a csv file to specify initial water levels and velocities at specific 2D cells. It can be used for all 2D cells, or for specific local features. An example of using an
Example initial condition 2D file.
IC_Midnight_Lake_001.csv - This lake resides over six TUFLOW FV cells
ID, WL, U, V
23, 1.1, 0.0, 0.0
28, 1.1, 0.0, 0.0
29, 1.1, 0.0, 0.0
42, 1.1, 0.0, 0.0
45, 1.1, 0.0, 0.0
46, 1.1, 0.0, 0.05.15.5 Restart File
This section describes the reading of restart files for initial conditions. For instructions on the writing of restart files refer to Section 5.18.10.
Restart files also referred to as hotstart files are generated by TUFLOW FV to save model variables such as depth and momentum at a specific instant in time from a previous simulation. A restart file can be read as the initial condition for a subsequent simulation allowing the model to begin from previously computed results. Because the restart file is created from an earlier simulation the model mesh and bathymetry must be identical between the simulation writing the restart file and the simulation reading it.
The default behaviour is for the restarted model to start from the time saved within the restart file. This can be optionally overridden using the
The example below shows the reading of a restart file generated from a one month warmup simulation FR_20221201_20230101_001.fvc. This command starts the current simulation on 1 January 2023 using depth and momentum fields that have developed during the preceding month.