How to setup periodic boundary conditions in solid-solid heat transfer
 

Hi,
I am simulating thermal conduction in a solid-solid model, and there have no fluid. As show in figure. How to setup the periodic boundary conditions at LEFT and RIGHT faces, so that temperature difference between point M on the LEFT face and corresponding point M' on the RIGHT face is always 10K. TM-TM'=10K

When I set the LEFT and RIGHT faces's boundary conditions as the periodic, there is only upsteam bulk termperature I can change. I don't know how to set the temperature difference between LEFT and RIGHT faces. Please help me!

Thank.

https://i.loli.net/2018/07/19/5b503324d1f55.png

https://i.loli.net/2018/07/19/5b503aefbc34d.png

Anyone can help me?