Why are the du/dy values so low?

syler3321 · September 2, 2010, 18:42

Hi,
i am using ANSYS CFX 12. I am running a simulation of an empty computational domain. i used a log law profile to input the velocity at my inlet. When i checked the du/dy in CFX POST, i get values that are very small near the wall. This shouldnt be the case. du/dy should be large near the wall. Instead of getting values like 2000 plus, i get values near the range of 50 to 60. What is wrong? Can somebody help? my simulation is for a smooth wall.

syler3321 · September 11, 2010, 00:56

Anybody? i'm getting really deperate here

ghorrocks · September 11, 2010, 06:09

Are you aware of the hybrid versus conservative variable difference? Read the documentation about the difference between the types of variables and it may explain your question.

September 2, 2010, 18:42	Why are the du/dy values so low?	#1
syler3321 Member ralph Join Date: Jun 2010 Location: Calgary Alberta Posts: 38 Rep Power: 15	Hi, i am using ANSYS CFX 12. I am running a simulation of an empty computational domain. i used a log law profile to input the velocity at my inlet. When i checked the du/dy in CFX POST, i get values that are very small near the wall. This shouldnt be the case. du/dy should be large near the wall. Instead of getting values like 2000 plus, i get values near the range of 50 to 60. What is wrong? Can somebody help? my simulation is for a smooth wall.

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September 11, 2010, 00:56		#2
syler3321 Member ralph Join Date: Jun 2010 Location: Calgary Alberta Posts: 38 Rep Power: 15	Anybody? i'm getting really deperate here

September 11, 2010, 06:09		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Are you aware of the hybrid versus conservative variable difference? Read the documentation about the difference between the types of variables and it may explain your question.