[GeoMechanicApplication] Add Water Pressure Degrees of Freedom to Interface Elements #14040
Description
As a developer, I would like the interface element to have water pressure degrees of freedom, such that I can start adding the water pressure related contributions to the element (i.e. coupling, permeability, compressibility and fluid body flow).
In this first step, all water pressure related terms will still be zero, but it enables developers to start adding contributions
Note: For assembling the correct terms in the correct locations in the LHS matrix or RHS vector, we should keep in mind we'll move to a list of generic calculators (should they know how to assemble, or the element?)
The water pressure DoF are always at both sides of the interface
Acceptance Criteria
Given A line/surface interface element
When a user asks for the degrees of freedom of the element
Then next to the displacements, the water pressures are there
Given A line/surface interface element
When a user calculates the left hand side
Then the matrix contains zero-entries for the water pressure related parts and the displacement related part is correctly assembled into the matrix
Given A line/surface interface element
When a user calculates the right hand side
Then the vector contains zero-entries for the water pressure related parts and the displacement related part is correctly assembled into the vector