example_poroelasticity code

[Karl Igor Martins Guerra]

Hello dear community members,

I've been studying the `example_poroelasticity.m` code, and although I've grasped much of the code and the philosophy behind its implementation, I'm still struggling to decipher the following line that appears within the time loop:

rhsf(1 : G.cells.num) = orhsf(1 : G.cells.num)*dt + ct(1 : G.cells.num, 1 : G.cells.num)*p + fac*div*x(ind_s);


How can we deduce this line from the system of PDEs? I understand that only the fluid rhs updates with time because the elasticity PDE is taken as elliptic and time appears "implicitly" in the update of p(x, t). But how is this right-hand side of the fluid updated with the above line of code? Why do we have the presence of the divergence of the solid part?

Best regards,
Karl