Help to detect the cause of divergence

Helium · July 15, 2019, 09:33

Hi guys,

I am performing a simulation where air flows through a heated channel (DO model and energy eq. on). Essentially my aim is to see how temperature of fluid varies when air leaves out from the outlet (pressure outlet). The simulation is perfectly normal till 500 iterations: at this point, there is a peak in continuity equation and air velocity raises to the incredible value of 250000 m/s (velocity inlet at 1 m/s as starting value). Okay, the channel is not so large (it's just few mm), but honestly this does not justify this situation...
Mesh quality is also okay and model dimensions are good... I do not know what to think, this never happened to me before.

Ideas?

Thanks

seph · July 15, 2019, 15:46

Might be the DO model, have you tried without radiation? Maybe also try the P1 or other models.

July 15, 2019, 09:33	Help to detect the cause of divergence	#1
Helium New Member Josh Join Date: May 2019 Posts: 16 Rep Power: 7	Hi guys, I am performing a simulation where air flows through a heated channel (DO model and energy eq. on). Essentially my aim is to see how temperature of fluid varies when air leaves out from the outlet (pressure outlet). The simulation is perfectly normal till 500 iterations: at this point, there is a peak in continuity equation and air velocity raises to the incredible value of 250000 m/s (velocity inlet at 1 m/s as starting value). Okay, the channel is not so large (it's just few mm), but honestly this does not justify this situation... Mesh quality is also okay and model dimensions are good... I do not know what to think, this never happened to me before. Ideas? Thanks

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July 15, 2019, 15:46		#2
seph New Member Join Date: Jul 2017 Posts: 3 Rep Power: 9	Might be the DO model, have you tried without radiation? Maybe also try the P1 or other models.