Simulating Wind Tunnel Experiments- Test Facility nozzle and constant

[FlyingGrimReaper]

I am curious about what exactly the limits of Flow Simulation are for SolidWorks. I was working on a thesis (completed and cleared) which was to analyze a scramjet isolator scaled up for 10 and 100 times the cross section. The initial CFD analysis was to simulate M=1.8 airflow entering from a C-D (converging-diverging) nozzle into a scramjet isolator.

The overall CFD results matched the experiemnts however I was not getting the correct contour plots for the flow. In scramjet isolator operation, there is supposed to be a normal shock train which develops. (I posted link of what should be seen on page 252.)

Now the simulation had a constant exit pressure boundary condition. The experiment itself used a throttled valve to control the back pressure (i.e. increases the pressure values as it closes).

This comes to my question, is flow simulation capable of creating a boundary condition which can increase the pressure to a maximum at an inlet or exit for a time dependent simulation? This parameter is essential for simulating back pressure and creating the shock train. This should also be within the high Mach flow conditions for Flow Simulation.

 

[SteveMartin]

You can create time-dependant boundary conditions. Not sure if that's what you're looking for, or if you're looking for a boundary that changes in response to some other variable in the study. I *think* that's possible too, but it's beyond the scope of what I know how to do.

Anyhow, to make the BC a function of time, click the Fx button next to where you would input a constant property value. You should get a 'dependency' window pop-up. At the top of the window will be a drop-down for Constant, F(time) - table, or Formula Definition. I'm not sure how to use 'Formula Definition' (never had to), but entering a table of time and BC values is easy enough. Note that if you haven't yet set the study to be time dependant, the F(time) - table option will not be available.

All this is based on Solidworks/FloWorks 2008. Exact method may vary in future versions.

 

[FlyingGrimReaper]

No that helps alot, I was trying the f(x) command to simulate the initial conditions inside the airflow, but never could get the correct mach number and pressure for the B/C with respect to time.