Help to create a CEL expression for Step function

mayj · November 2, 2013, 04:25

Hi Glenn
I sure appreciate your suggestion. This isn't something I can find in the library. I've looked at all relevant materials and have run many simulations. I need to get some ideas to ensure I'm on the right track.

ghorrocks · November 2, 2013, 23:03

An essential skill for any researcher is the ability to find out what other researchers have done in your field. You are not going to get very far without it. You really should do some research so you understand ways mixing can be measured to determine what is appropriate for your situation.

I do not know ways of measuring mixing because I do not need to in my field. I can guess a few ways, but it would be just a guess. If I needed to measure mixing I would be doing a literature search to find what the state of the art is. There is no point using a metric when you later find another one is much more appropriate. So do the research and get it right first time.

mayj · November 3, 2013, 00:07

Sure, thanks

mujahidbadshah · January 8, 2018, 01:08

I want to run a transient simulation for 10 seconds with a time step of 0.1 seconds. I have a rectangular domain with water as the working fluid. I want to provide an inlet normal velocity of 12 m/s for only 1 second and then want it to become zero suddenly after 1 second.

Kindly some body help me to write a step function expression or any other CEL expression to achieve my inlet velocity condition.

ghorrocks · January 10, 2018, 15:49

Set the inlet velocity to

if(t<1[s],12[m s^-1],0[m s^-1])

CEL is very simple and is explained well in the documentation. Make sure you read the CFX reference guide on the CEL, and do the CFX tutorials.

mujahidbadshah · January 10, 2018, 23:41

Hi Glenn,

Thanks a lot for your reply and help.

November 2, 2013, 04:25	step function	#21
mayj Member may Join Date: Jul 2013 Posts: 31 Rep Power: 12	Hi Glenn I sure appreciate your suggestion. This isn't something I can find in the library. I've looked at all relevant materials and have run many simulations. I need to get some ideas to ensure I'm on the right track.

November 2, 2013, 23:03		#22
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	An essential skill for any researcher is the ability to find out what other researchers have done in your field. You are not going to get very far without it. You really should do some research so you understand ways mixing can be measured to determine what is appropriate for your situation. I do not know ways of measuring mixing because I do not need to in my field. I can guess a few ways, but it would be just a guess. If I needed to measure mixing I would be doing a literature search to find what the state of the art is. There is no point using a metric when you later find another one is much more appropriate. So do the research and get it right first time. mayj likes this.

November 3, 2013, 00:07	step function	#23
mayj Member may Join Date: Jul 2013 Posts: 31 Rep Power: 12	Sure, thanks

January 8, 2018, 01:08	Step Function for Inlet Velocity	#24
mujahidbadshah Member Mujahid Badshah Join Date: Oct 2015 Posts: 32 Rep Power: 10	I want to run a transient simulation for 10 seconds with a time step of 0.1 seconds. I have a rectangular domain with water as the working fluid. I want to provide an inlet normal velocity of 12 m/s for only 1 second and then want it to become zero suddenly after 1 second. Kindly some body help me to write a step function expression or any other CEL expression to achieve my inlet velocity condition.

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January 10, 2018, 15:49		#25
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Set the inlet velocity to if(t<1[s],12[m s^-1],0[m s^-1]) CEL is very simple and is explained well in the documentation. Make sure you read the CFX reference guide on the CEL, and do the CFX tutorials.

January 10, 2018, 23:41		#26
mujahidbadshah Member Mujahid Badshah Join Date: Oct 2015 Posts: 32 Rep Power: 10	Hi Glenn, Thanks a lot for your reply and help.