PDE Model Boundary Conditions

Hi Everyone,

I have a question regarding the Matlab PDE Model Boundary Conditions.

Currently, I am working with a 2D mesh with heatflux on one egdes. This egdes has 9 nodes. When I looked at state.u I recognized that this is a 1x12 array. But why?

Answer 1

[Torsten]

If you output state.x and state.y in the function, you can see to which evaluation points state.u belongs.

[Patrick Frey]

Do you mean location.x and location.y?

[Torsten]

Sorry, yes - that's what I mean.

[Patrick Frey]

With location.x and location.y I can see the evaluation points. But these points are different than the nodes on the edge. If I use a temperature as boundary condition instead of heatflux than the evaluatuion points are the same as the nodes. Why isn't this with heat flux?

[Torsten]

If you use a heatflux condition, the temperatures at the boundary are not known in advance. I'm not sure how the PDE Toolbox approximates the temperatures in the node points. Maybe with some helper points to approximate dT/dn in the node points ?

But if you need this information reliably, you should contact MATLAB support.

[Patrick Frey]

Thank you very much for your help