sudden drop in solver monitor

jiguozhao · February 25, 2011, 03:27

Dear all:
I was trying to simulate gas going across membrane process. the porous media separate the gas domain into feed side and permeate side. the feed pressure is as large as 200kpa. and the perm side is 0 pa. the permeability is very small so the resistance for gas passing through is large. I set velocity inlet as 0.0003 m/s, opening outlet with 0 pa.
why the iteration shows a sudden drop like the pic in attachment. although it converged, the result obtained is non sense.
so is there any one who can tell me why there is a sudden drop in solver monitor?
Kind regards
Ji Guozhao
g.ji@uq.edu.au

ghorrocks · February 25, 2011, 06:44

Try using double precision numerics.

jiguozhao · February 26, 2011, 19:55

Quote:

Originally Posted by ghorrocks

Try using double precision numerics.

Excuse me Sir! can you tell me how to set double precision. is it in cfx pre?
with regards
Ji Guozhao

ghorrocks · February 27, 2011, 06:34

Either in Pre or in solver manager (in advanced options).

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February 25, 2011, 06:44		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Try using double precision numerics.

February 27, 2011, 06:34		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Either in Pre or in solver manager (in advanced options).