Hot and cold spots along the axes

MSHowes · February 11, 2013, 16:17

Hello,
I'm modeling a rotating cylindrical flow and I'm seeing narrow hot and cold areas appearing on either side of the x and y axes (my axis of rotation is z). The temperature should remain uniform so this looks like numerical error. Has anybody seen this?

ghorrocks · February 11, 2013, 18:06

Have you read the FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

MSHowes · February 12, 2013, 09:53

Hi, thank you for your response. Yes, I have read the FAQ. Unfortunately it basically says "try everything"-- I wish I had the time. What's puzzling to me is that my momentum and pressure results look great; it's just the temperature that exhibits this error along the axes. I'm tracking the residuals and the heat transfer residuals are on a par with the momentum residuals. I've tested it on three grids so far. The hot/cold spots appear within a few time-steps and never go away.

ghorrocks · February 12, 2013, 18:44

With such a general question with no description of what you are modelling, then how do you expect anything but a general answer? But the real answer will be one of the things discussed in the FAQ - your job is to find which one.

February 11, 2013, 16:17	Hot and cold spots along the axes	#1
MSHowes New Member Join Date: Sep 2012 Posts: 8 Rep Power: 6	Hello, I'm modeling a rotating cylindrical flow and I'm seeing narrow hot and cold areas appearing on either side of the x and y axes (my axis of rotation is z). The temperature should remain uniform so this looks like numerical error. Has anybody seen this?

February 12, 2013, 09:53	hot and cold spots	#3
MSHowes New Member Join Date: Sep 2012 Posts: 8 Rep Power: 6	Hi, thank you for your response. Yes, I have read the FAQ. Unfortunately it basically says "try everything"-- I wish I had the time. What's puzzling to me is that my momentum and pressure results look great; it's just the temperature that exhibits this error along the axes. I'm tracking the residuals and the heat transfer residuals are on a par with the momentum residuals. I've tested it on three grids so far. The hot/cold spots appear within a few time-steps and never go away.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
which Solver for Hot Cold Water mix	uwsa	OpenFOAM	14	May 28, 2017 06:04
good cold flow results but problem with hot flow	Rams	FLUENT	0	June 20, 2006 00:52
good Cold Flow Results but problem with Hot Flow	Rams	FLUENT	1	June 18, 2006 19:59
good cold flow results but problem with hot flow,.	Rams	FLUENT	0	June 13, 2006 11:08
good Cold Flow Results but problem with Hot Flow	Rams	CFX	2	June 13, 2006 03:30

February 11, 2013, 18:06		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,639 Rep Power: 105	Have you read the FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

February 12, 2013, 18:44		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,639 Rep Power: 105	With such a general question with no description of what you are modelling, then how do you expect anything but a general answer? But the real answer will be one of the things discussed in the FAQ - your job is to find which one.