Assessment of Residuals

eRzBeNgEl · August 30, 2011, 04:33

Hu guys,

this is a general question. How do you assess the residuals. For example in a Simulation of mine they just get on the level of 1E-02, but all my other parameters (pressure, massflow, e.g.) are on an constant level.

I have got a similar simulation, where the residuals lie between 1 to 10...all other values are constant and in comparison to a labor test very good caclulated.

So how do I have to assess the residuals?

Sim Data: Steady State, ke model, Segregated Flow, Rho = const.

Thanks for help

cfdnewbie · September 4, 2011, 07:22

Which residuals are you talking about? L inf, L1, L2? Which variable?

If you are solving for a steady state, I assumed you used an implicit scheme? Have you tried adjusting the CFL?

You wrote "segregated" flow...do you mean detached (abgeloest) by that? In that case, I'd really expect to see some vortex shedding, which is highly unsteady....

eRzBeNgEl · September 4, 2011, 10:22

Hi,

Thanks for your answer, my mesh resolution was too low, that was the problem.

Thanks for your help

cfdnewbie · September 4, 2011, 14:05

no problem, gerne.

August 30, 2011, 04:33	Assessment of Residuals	#1
eRzBeNgEl Senior Member Join Date: Dec 2010 Posts: 135 Rep Power: 15	Hu guys, this is a general question. How do you assess the residuals. For example in a Simulation of mine they just get on the level of 1E-02, but all my other parameters (pressure, massflow, e.g.) are on an constant level. I have got a similar simulation, where the residuals lie between 1 to 10...all other values are constant and in comparison to a labor test very good caclulated. So how do I have to assess the residuals? Sim Data: Steady State, ke model, Segregated Flow, Rho = const. Thanks for help

September 4, 2011, 07:22		#2
cfdnewbie Senior Member cfdnewbie Join Date: Mar 2010 Posts: 557 Rep Power: 20	Which residuals are you talking about? L inf, L1, L2? Which variable? If you are solving for a steady state, I assumed you used an implicit scheme? Have you tried adjusting the CFL? You wrote "segregated" flow...do you mean detached (abgeloest) by that? In that case, I'd really expect to see some vortex shedding, which is highly unsteady.... eRzBeNgEl likes this.

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September 4, 2011, 10:22		#3
eRzBeNgEl Senior Member Join Date: Dec 2010 Posts: 135 Rep Power: 15	Hi, Thanks for your answer, my mesh resolution was too low, that was the problem. Thanks for your help

September 4, 2011, 14:05		#4
cfdnewbie Senior Member cfdnewbie Join Date: Mar 2010 Posts: 557 Rep Power: 20	no problem, gerne.