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Convergence Problem - Transient Simulation

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Old   July 15, 2018, 09:36
Default Convergence Problem - Transient Simulation
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gemxx
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Hi all,

The residuals are about 10^-6 at the end of steady simulation.
After that, I start the unsteady(transient) simulation by using steady simulation data as input.

The residuals should continue to decrease from 10^-6 to lower values. But they rapidly increase to 10^-1. Then, they slowly goes to 10^-6 within 20 inner iterations.

My purpose is to reach 10^-9 level convergence at least. It can be possible to achieve this by using 10^-6 level steady simulation convergence. But I don't understand why the transient simulation rapidly increase to 10^-1 after steady simulation.

I send a photo of the residuals in attachment. Could you please tell me the reasons of this situation ?

https://ibb.co/cxKOBo

I want the transient simulation residuals to continue decreasing after the steady simulation like that :

https://ibb.co/e7jnMo
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