How to change boundary type dynamically in Ansys 2019 R1?

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  • Last Post 27 February 2019
tubiy posted this 26 February 2019

Hello, does someone know how to change the boundary type during a transient simulation when a certain condition is satisfied?

I need this in order to replicate valve scenarios to selectively block or allow flow through a certain boundary.  

in my case if the surface (B) temperature is less than 75̊ °C, surface A needs to be defined as a "wall" and when the surface(B) temperature is above 75̊ °C, surface A needs to be defined as an "interior".

if there is another option without creating a UDF file I will be glad to hear about it.  

Thank you.

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abenhadj posted this 26 February 2019

I guess with UDF and scheme if dynamic mesh events are not appropriate.

Best regards,

Amine

tubiy posted this 26 February 2019

Hi, 

Thanks for your prompt answer.

I am not interested in a transient phenomenon around the ball valve I just need a barrier that will close and open when a certain condition is satisfied, so I don’t want to resolve the problem with dynamic mesh, it’s complicated for me.

I am not familiar with a UDF file, I just heard about it as an option when you don't have a standard boundary condition, for example. I will be glad if you have a similar UDF  that I could work with / change it.

And I thought there might be another option like using Expressions which could  Save me tinkering with a UDF file. Or an idea for something else that will illustrate the barrier, like a porous jump boundary condition.

 

 

 

abenhadj posted this 26 February 2019

Check this: https://studentcommunity.ansys.com/thread/apply-udf-for-a-fixed-period-of-time/

 

Dynamic Mesh Event do not really require dynamic mesh.

Best regards,

Amine

tubiy posted this 26 February 2019

I don't know the exact time the temperature is less than 75̊ °C or above 75̊ °C and it's happening a lot, so is Dynamic Mesh Event still relevant?

 

I need to check the temperature at surface B during the simulation. And just when the temperature is less than 75̊ °C or above 75̊ °C,  I need to change the boundary condition at the surface A.

 

 

 Best regards,

Tubi.

abenhadj posted this 26 February 2019

Yes you can do that by using some scheme commands like in the post shared here.

Best regards,

Amine

tubiy posted this 26 February 2019

sorry that I am asking you again, I don't understand the steps that I need to do for solving my problem ( I just now starting to learn Ansys Fluent)

how and what exactly do I need to do? I will glad if you can elaborate on what you mean.

I need to write some scheme commands and write a UDF file?

Best regards,

Tubi.

 

abenhadj posted this 26 February 2019

If you have right started leaning Fluent I recommend at first going through some tutorials. Whenever you have done that then please check the content of the post I shared. In your case, you need to create a report definition for the temperature. Whenever this temperature is larger then you instruct Fluent to do some boundary change. Scheme will be required.

 

Best regards,

Amine

abenhadj posted this 26 February 2019

Just start the Online Help (Hitting F1 in Fluent wherever you are) then go to the main page of Fluent help and you will have all standard tutorials. For Scheme we do not have tutorials.

Best regards,

Amine

kkanade posted this 27 February 2019

plz check following post for checking help. 

https://studentcommunity.ansys.com/thread/how-to-access-the-ansys-online-help/

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