FVM boundary conditions
 

Hi there:

I'm solving equations using finite volume methods on an irregular triangular mesh. I construct my control volumes as shown in the attached file. My question is, how do I deal with nodes at boundaries? Nodes on the edge of my domain only have 4 neighbouring nodes, while corners only have 3 neighbouring nodes. Consequently, I cannot construct a control volume like I have for non-boundary nodes. Do I simply construct a "partial" control volume? Any suggestions or advice would be appreciated.

Hello Nereus

What you need to look into is something call "ghost cell" or "ghost node" to take care of the flux across the boundary face. I suggest you read the chapters in Blazek's book. It explains node-based FVM in very practical way. Also, you were right that you only need to use the "partial" volume, as the "ghost node/cell" only provides flow variables to allow you to calculate the flux and does not occupy any volume.

Cheers,
Shenren

Thanks for the reply, Shenren. That book is exactly what I was looking for!