What if we want to use two component in a bc?

[tjboise]

Hi Dr. Lu,

I meet a problem in writing a boundary condition in creep flow simulation. In the outlet, the pressure boundary is always written in:

Thus, the bc contains velocity u (including u_x and u_y) and pressure p. And, the bc is a neuman bc with three components (u_x, u_y and p).

However, For the bc: deepxde.icbc.boundary_conditions.NeumannBC(geom, func, on_boundary, component=0) we can only use one component in each bc. What could I do to solve this problem?

Thanks.

[lululxvi]

Use OperatorBC, see BC questions in FAQ.

[katayooneshkofti]

@lululxvi I have a question that may seem rudimentary because my major is not mathematics. I will be grateful if you answer my question. If we have x and t as independent variables (inputs) and we also have 3 dependent variables, such as g, u and w, for defining the following boundary condition, should I use Robin or OperatorBC: dg/dx = u + w

[lululxvi]

Either one is OK.