Help with handling named expressions in pyfluent

[ShardulKamatNU]

Hello, I am somewhat inexperienced with both pyfluent and fluent named expressions.

I am trying to edit a named expression called expr1 which is already defined in a fluent case file, by loading the case and data into a pyfluent session and using pyfluent commands to change the definition of the named expression. I want to add a variable to the definition of expr1. However, I have been unable to get this to work.

I have attached the case and data file in a zipped folder, if you wish to try to replicate my issue.
casdat.zip

expr1 is defined initially as having the value of 2.0.
After loading the case and data files, I run the following command to view the properties of the named expression
solver.tui.define.named_expressions.list_properties("expr1")
resulting in the following output

expr1
-----
Definition       : 2.0
Description      : 
Input parameter  : No
Output parameter : No
Used in          : 0 places
Type             : Double
Valid            : Yes
Single-valued    : Yes
Constant         : Yes
Constant-valued  : Yes
Value            : 2
Dimension        : 

which is as expected.

I can successfully change the definition of expr1 to 3.0 by using the following command
solver.tui.define.named_expressions.edit("expr1","definition","3.0")
this gives no output, so it is checked by using
solver.tui.define.named_expressions.list_properties("expr1")
resulting in the following output

expr1
-----
Definition       : 3
Description      : 
Input parameter  : No
Output parameter : No
Used in          : 0 places
Type             : Double
Valid            : Yes
Single-valued    : Yes
Constant         : Yes
Constant-valued  : Yes
Value            : 3
Dimension        : 

Now, the problem. I try to add the static temperature to the definition. I want the definition of expr1 to be 3.0*T. T is the alias for the StaticTemperature variable
solver.tui.define.named_expressions.edit("expr1","definition","3.0*T")
this gives the output

Error: eval: unbound variable
Error Object: 3.0*t
Invalid value

Error: fromScheme: string
Error Object: #f

now if I do list_properties
solver.tui.define.named_expressions.list_properties("expr1")
I get the output

expr1
-----
Definition       : #f
Description      : 
Input parameter  : No
Output parameter : No
Used in          : 0 places
Type             : Double
Valid            : Yes
Single-valued    : Yes
Constant         : Yes
Constant-valued  : Yes
Value            : 3
Dimension        : 

The definition has changed to the floating point exception object, but the value is unchanged.

I am not sure what is happening.
I get similar errors if I try to add the units of meters to expr by doing
solver.tui.define.named_expressions.edit("expr1","definition","3.0[m]")
resulting in the output

Error: eval: unbound variable
Error Object: 3.0[m]
Invalid value

Error: fromScheme: string
Error Object: #f

I am not sure if my syntax is wrong or something else? I appreciate any help.

[mkundu1]

Looking at the error message, you may need to add additional quotes around the expression: solver.tui.define.named_expressions.edit("expr1", "definition", '"3.0*T"')

See this note about TUI API usage. It is better to verify whether the arguments are of string type from a saved Fluent journal.

With Fluent 2023 R1 or later, you can also use settings API for setting up named expressions - https://github.com/ansys/pyfluent/blob/main/tests/test_solvermode/test_named_expressions.py