Boundary condition changes in transient simulation

Numerical methods and mathematical models of Elmer
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rcbeta
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Boundary condition changes in transient simulation

Post by rcbeta »

I am setting up to run a transient RANS problem. I have attached the case.sif file for reference.

The geometry is an inclined plate, 2D, in a rectangular flow domain. The inlet has a constant velocity profile for now. Eventually, I will modify the boundary condition to reflect a turbulent flow profile. At present, I am just trying to work the bugs out prior to running the actual simulation that I want to run.

The simulation starts and runs fine, but at roughly 2/3 of the way through the simulation the inlet boundary condition changes. The velocity had been set to Velocity 1 = 0.05. Everything is running fine and then when I am post processing the output, there is a step change in the solution (I am only keeping a portion of the output).

When analyzing the output in Paraview, I note that the inlet velocity condition went from 0.05 to 0.01 ...

Any thoughts or suggestions? Anyone seen this before? The solution appears to reach a steady state at about this time - so I am not sure if that has an impact or not.

Thanks in advance for any feedback.

Randy
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raback
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Re: Boundary condition changes in transient simulation

Post by raback »

Hi

My guess is that you have old .vtu files present and only partially overwrite them. Perhaps your previous test runs had different inlet velocity?

-Peter
rcbeta
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Re: Boundary condition changes in transient simulation

Post by rcbeta »

Hmmmm ... I will have to check into that. I am not sure, but ... maybe? Thanks for the suggestion - I greatly appreciate it.
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