I want to define a run where some of the variables in the initial condition use specified value or CEL expressions and others use values from initial values file. Is it possible to do so?
Yes. It is possible. For variable field Initialization, the CFX solver accepts four possible options:
- Automatic with value
This is the most common option and is recommended for most cases. Initial values will be read from an initial values file, if specified, or from an interpolated solution. If neither of these is available, the specified value or CEL expression is used. A value or expression must be specified.
Initial values will be read from an initial values file, if specified or from an interpolated solution. If neither of these is available, the default Initialization will be applied. A value or expression cannot be specified.
The specified value or CEL expression is always used. Note that for restarts, using the 'Value' option will ignore the field in any initial values file. A value or expression must be specified.
The solver generates a suitable initial field. A value or expression cannot be specified.
So, if one can set some of the variables Initialization option to 'Value', those variables will use specified value or CEL expressions. Other variables can be set to `Automatic with value` and will be initialized from the initial values file, if there is one.
Currently, only the reduced subset of 'Automatic' and 'Automatic with Value' options is available in CFX-Pre. There are several ways to get access to the 'Value' option. Three methods are described below.
1. Use Command Editor in CFX-Pre.
- Right click 'Initialization' and select 'Edit in Command Editor'
- For the variable where a specified value or CEL expression is needed, change the option from 'Automatic with Value' or 'Automatic' to 'Value'.
- Add another line to set its value, e.g. Temperature = 300 [K]
- Click 'Process'. You will get some error message, saying that 'Value' is not allowed. You can ignore these error messages.
- Save the modified definition file and restart the run using the previous results file for the initial values fileand the modified definition file as the definition file for the run.
2. Edit the definition file with the command file editor. An example of setting the 'Value' option for temperature in an individual domain is shown below:
- Open the CFX solver manager
- Select 'Tools > Edit Definition File', choosing the definition file you are using for your run
- Open the tree: flow/domain/initialisation/initial conditions/temperature
you should see something similar to
option -> automatic with value
temperature -> 300 [K]
- Double click on option Automatic with value and change the selection to Value
- Save the modified definition file and restart the run using the previous results file for the initial values file and the modified definition file as the definition file for the run.
3. Those familiar with editing command language manually and using the cfx5cmds utility can use this route to access the full set of Initialization options.