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Old   May 27, 2013, 08:31
Exclamation setting Timestep
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Francesco
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Hi everybody,
I'm running a steady simulation of a centrifugal blower.
Usually I do the following:
1. I set a really small timestep order to E-06 with Upwind scheme;
2. after 1000 iterations I switch timestep to E-05 with upwind scheme;
3. when physical properties which I monitor are stable, I switch to Blend Factor =0.75 (so not completely High resolution) and wait for a new stable state.

This process usually works, but not now.
Until I use upwind solution seems reach the convergence, but when I switch to Blend factor 0.75 ( i tried 0.6 as well) it doesn't happen.
I changed a lot of timestep between E-5 and E-7, but seems no works.
Someone has an idea about this behaviour and about what I should do?

Thanks
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Old   May 27, 2013, 18:50
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Glenn Horrocks
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This is typical behaviour when you switch to a more accurate discretisation scheme. It means your simulation is not very numerically stable. In your case this probably means you need better mesh quality.
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Old   May 28, 2013, 03:08
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Francesco
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I'll do a new mesh.
Thanks man. U precious!
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