Residual spike while switching form serial to parallel.

nvarma · May 26, 2016, 10:41

Can anyone explain why there is a spike in residuals as I switch (write cas and dat, open in parallel) from serial to parallel run on fluent?

nvarma · May 27, 2016, 10:12

Update:

So not only is there a residual spike, it diverges immediately. The simulation can go on for thousands of iterations in serial but not even hundred on parallel.

Anybody?

`e` · May 27, 2016, 18:27

Could you show us your mesh with the partitions outlined? Be careful of having partition boundaries where important flow characteristics occur (non-linear changes in velocity); especially if you're using a second order discretisation scheme (partitions only overlap one cell on the partition boundary). Have you tried running in parallel from initial conditions or only from a serial-produced result?

May 26, 2016, 10:41	Residual spike while switching form serial to parallel.	#1
nvarma Senior Member nm Join Date: Mar 2013 Posts: 100 Rep Power: 13	Can anyone explain why there is a spike in residuals as I switch (write cas and dat, open in parallel) from serial to parallel run on fluent?

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May 27, 2016, 10:12		#2
nvarma Senior Member nm Join Date: Mar 2013 Posts: 100 Rep Power: 13	Update: So not only is there a residual spike, it diverges immediately. The simulation can go on for thousands of iterations in serial but not even hundred on parallel. Anybody?

May 27, 2016, 18:27		#3
`e` Senior Member Join Date: Mar 2015 Posts: 892 Rep Power: 18	Could you show us your mesh with the partitions outlined? Be careful of having partition boundaries where important flow characteristics occur (non-linear changes in velocity); especially if you're using a second order discretisation scheme (partitions only overlap one cell on the partition boundary). Have you tried running in parallel from initial conditions or only from a serial-produced result?