Discussion Forum

I'm trying to do a simple transient analysis of conduction through 2 interfaces. My test run is basically 2 cubes of 100 mm length. One cube at an initial temperature of 1800K and the other with initial T at 273.15 K. Both using library material properties for AISI 4340 steel. After observing the plots, the temperature of one cube constantly stayed at room temperature, so it seemed there was no heat flow through one of the cubes. I've reread the documentation on assigning identity pairs and believe that I have done it right. Well maybe..

Procedure
1. Draw 2 cubes of 100mm length
2. Select Draw->Create pairs.
3. Physics -> Identity pairs->identity Boundary pairs
4. Select 1 source face from cube 1 and 1 destination face from cube 2.
5. Apply Sub domain and Boundary conditions with ambient temperature.

The only thing that I can think of is that I modeled 2 cubes a certain distance apart. In other words, the 2 interfaces are not stuck together. I am assuming that Comsol can understand the continuity relationship from the identity pairs. Therefore the program shouldn't require the 2 cubes to be combined at the interface. Another reason why I did this is because my real simulation is a combination of two complicated parts being imported. Therefore it benefits me if the interfaces don't have to be mated together, if I just use identity pairs on the required faces.

Any input would be appreciated.