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How is convergence indicated in the residuals for a unsteady flow simulation in ANSYS

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Old   June 29, 2019, 13:59
Default How is convergence indicated in the residuals for a unsteady flow simulation in ANSYS
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Abdullah Tariq
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Situation) Guys I am currently running a unsteady CFD simulation of a fuel jet injected perpendicular to air moving in a channel. Can you kindly tell me what the residual plots of (residual vs iteration) should indicate to show that the simulation has converged? I know there are other things too one must observe e.g. monitors, max flux imbalances...My question is in regards to residuals only
My time step=0.001s
total simulation flow time=0.56 sec
number of iteration per time step=20
For a unsteady simulation the residuals may be more than 1e-3 at a certain moment in time and then be less than 1e-3 at another moment in time.
Q1)Does that mean for the situation when the residuals are below 1e-3 the field variables obtained in the domain would be reliable for that moment in time only?
Q2)Then, to obtain the value of field variables which would be reliable for all time, do we have to ensure that the residuals, despite their fluctuations, stay below 1e-3 for any more flow time

I have attached screencaptures of my mesh and geometry
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File Type: jpg geometry.JPG (17.7 KB, 13 views)
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