Discussion Forum

Hello,
I am very new to Comsol and attempting to set up a problem where I have a shock originating in the upstream of a 1-D duct system composed of different diameter ducts which are serially connected. I'm starting from the very general shock tube problem solution (1-D spatial, unsteady) given on the Comsol website.
A major difference in my desired setup is that this sample model demonstrates the problem where a membrane separates a high pressure gas field and a low pressure field, but both of the same gas. This sample model uses the general form pde physics.
I am interested in tracking the shock and overall flow field attributes as the shock propagates thru this duct system. But my desired domain is a little more complicated, and I'm having some difficulty figuring out how to tailor the sample model inputs to what I need, namely: (1) setting up the initial flow field, where I have gas of different properties (gamma, P, T, rho, etc.) than what's in the downstream, (2) setting the initial P, T, rho at the shock location as different than either upstream or downstream flow fields (preferably I'd like to be able to input the shock location and flow field attributes as a parametric), and (3) establishing the boundary conditions and coefficients that quantify the differences in duct diameter along the length of the desired flow field (interested really in getting duct area effect and not necessarily viscous effect at this time).
I realize these questions involve pretty long, detailed answers, but my basic question is: for my needs above, is this general form pde module still appropriate? If not, can you suggest a better start point? Also, any recommendations for assisting with my listed items above would be appreciated.
Thanks,
Mike G.