Hello, I would like to model a shock tube. I plan on using a simple 2-D case with a long thin pipe leading out of a reservoir. At the interface I want to model a diaphragm that I can rupture once the pressure in the reservoir has stabilised at the value I require. Has anyone any suggestions on the best way to model this? I was planning on having a wall at the intersection of the pipe and reservoir and then just changing this to an interior boundary condition. Is there a way of automating this to happen after a particular time in an unsteady simulation? Thanks in advance for your help. James

Hi; Oh, yes. You can model shock tube problem with fluent very well by unsteady calculation. I have done this by fluent5.23 two years ago. You do not need to model very long pipe, a pipe with L/d=10 is good. You do not need model the diaphragm with a wall or ... You should define two fluid zones in gambit for your shock tube right and left regions. Set the interface as interior. In fluent, you should patch the pressure and density or temperature of two regions for initial condition. Then start calculations. Note that you should use a time step of O(.0001) or lower for a shock tube problem. Hope this help you Roozbeh

Thank you very much, that is of great help. I will try it right away.