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-   -   Help to create a CEL expression for Step function (https://www.cfd-online.com/Forums/cfx/83805-help-create-cel-expression-step-function.html)

mayj November 2, 2013 04:25

step function
 
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

step function
 
Sure, thanks

mujahidbadshah January 8, 2018 01:08

Step Function for Inlet Velocity
 
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.


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