Coordinate frame "bug"

Guille1811 · October 15, 2017, 05:53

This has happened to me a few times with different simulations:

I define a coordinate frame in cfx pre using "point and normal" option, the coordinate frame becomes well defined, i run the simulation and the results are ok. Later on when i change some setting (say from 600 rpm to 800 rpm), i run the simulation and the results are far from coherent. Reason? Magically the coordinate frame inverted itself, in other words the z axis became the -z axis, without me touching any of its definition.

This is quite random and anoying because it doesnt let you automate some simulation runs.

Does anyone know how to fix this?

Guille1811 · October 16, 2017, 11:37

Cmon guys, nobody has this problem?

ghorrocks · October 16, 2017, 18:21

I do not do that sort of simulation much, so no, I do not have the problem.

If you think it is a bug then report it to ANSYS. Then it can be fixed.

JuPa · October 25, 2017, 11:49

Quote:

Originally Posted by Guille1811

This has happened to me a few times with different simulations:

I define a coordinate frame in cfx pre using "point and normal" option, the coordinate frame becomes well defined, i run the simulation and the results are ok. Later on when i change some setting (say from 600 rpm to 800 rpm), i run the simulation and the results are far from coherent. Reason? Magically the coordinate frame inverted itself, in other words the z axis became the -z axis, without me touching any of its definition.

This is quite random and anoying because it doesnt let you automate some simulation runs.

Does anyone know how to fix this?

When you do point and normal don't provide coordinates just by selecting a named selection or just by clicking on a region of the mesh/domain. Actually explicitly provide the coordinates. And make sure you insert the coord frame absolute and not to the nearest mesh node. There is an option for this.

Guille1811 · October 25, 2017, 12:03

In my case that domain will be rotating along de vertical axis so the coordinates of the "point" will be changing over time, how can i implement that option then?

JuPa · October 25, 2017, 12:28

Post a picture let me see what you got (no innuendo intended)

October 15, 2017, 05:53	Coordinate frame "bug"	#1
Guille1811 Member Join Date: Oct 2017 Posts: 89 Rep Power: 8	This has happened to me a few times with different simulations: I define a coordinate frame in cfx pre using "point and normal" option, the coordinate frame becomes well defined, i run the simulation and the results are ok. Later on when i change some setting (say from 600 rpm to 800 rpm), i run the simulation and the results are far from coherent. Reason? Magically the coordinate frame inverted itself, in other words the z axis became the -z axis, without me touching any of its definition. This is quite random and anoying because it doesnt let you automate some simulation runs. Does anyone know how to fix this?

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October 16, 2017, 11:37		#2
Guille1811 Member Join Date: Oct 2017 Posts: 89 Rep Power: 8	Cmon guys, nobody has this problem?

October 16, 2017, 18:21		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	I do not do that sort of simulation much, so no, I do not have the problem. If you think it is a bug then report it to ANSYS. Then it can be fixed.

October 25, 2017, 12:03		#5
Guille1811 Member Join Date: Oct 2017 Posts: 89 Rep Power: 8	In my case that domain will be rotating along de vertical axis so the coordinates of the "point" will be changing over time, how can i implement that option then?

October 25, 2017, 12:28		#6
JuPa Senior Member Mr CFD Join Date: Jun 2012 Location: Britain Posts: 361 Rep Power: 14	Post a picture let me see what you got (no innuendo intended)