How to declare a variable in prj file?

I am using a Parameter (type = function) applied on a boundary mesh. In the tag, I can define only x,y,z as variables. But I want to use another variable also in this, whose value is already defined in the beginning of prj file. Is this possible?

For e.g.
let hydraulic gradient ihor= 2.7472 x 10^(-4)


And is there any way to define some independent and dependent variables in the beginning of prj file, so that OGS solves their value first and then applies them in the tag.


the parameter type Function is to define coordinate specific parameters. So, the function variables are restricted to x, y, z.

To define time depended functions use the curves tag.

Otherwise you may want to have a look to python based boundary conditions. There you can define Dirichlet or Neumann BC (also for source terms) using arbitrary function for within a python script. Just look at * Python Boundary Conditions* on the benchmark page.