unit vector direction at corner - PDE mesh

Hello,

My question relates to a heat transfer PDE problem I have set up. The geometry is a simple rectangle, the sides of which align with x and y axes of cartesian coordinate system.

When it comes to setting the boundary conditions, I define Neumann condition using n · (c∇u)+qu=g, where n is the normal unit vector. I am struggling to understand how n is determined in general by Matlab. I also want to know the direction of n for nodes on corners of my rectangular domain. Is it in x direction, y direction or at 45 degrees?

I'd much appreciate a bit of basic explanation.

Many thanks,

Sunil.

Answer 1

[Samatha Aleti]

You may refer to the following link for information on applying boundary conditions to PDE model

https://www.mathworks.com/help/pde/ug/pde.pdemodel.applyboundarycondition.html?s_tid=doc_ta

Hope this helps!