I am having troubles when selecting a face for my fluid subdomain and boudary condations. I am using a student version 12/13 and it does not come with the flow simulation tutorials, so I have replicated the following tutorial with lids included. http://personal.stevens.edu/~ffisher/me345/Tutorial_3_Heat_Exchanger.pdf. When I try to replicate 6-8 step 2 of the tutorial (Select the water inlet lid inner face (in contact with the fluid), I can only select the top of the lid or the side of it. I am not sure what I am doing wrong. I have tried making the lid stick out of the HX, flush with the HX, and even an exploded view (which I could select the botom face, but SW didnt like that when I went to hit ok).