Electric Field (UDF) - FLUENT

RGI · November 2, 2015, 05:01

Good morning everyone ...

I am doing a research using FLUENT, and I am trying to introduce an electric field to FLUENT through a UDF. The electric field is to be constant with a value that the user would define.

I have read that one can do that by solving the poissons equation for applied or induced potential, where the derivative of the potential can be taken to get the electric field. Such thing can be done by defining a UDF that I am not fully aware of.

I would appreciate it if someone can help in defining this UDF or if someone has an easier approach/way to define an electric field to FLUENT ...

Please note that the built in module MHD does not suit my problem ...

Thank you in advance ...

Kind regards

RGI · November 8, 2015, 03:10

Any one who can help?

LuckyTran · November 9, 2015, 00:10

I would have recommended the MHD module as a start

Can you elaborate on what you hope to accomplish by adding a constant electric field? If you want to define a constant electric field, it's like defining a constant scalar field or defining a global constant (like pi). This part is trivial and you do not need a poisson equation for it (it's constant everywhere). So what do you plan to do after? If you plan to do charged particle simulations in a fluid flow then you're back to to MHD.

RGI · November 13, 2015, 13:31

Hi ...

Many thanks Mr. LuckyTran for your reply ... I really appreciate it ...

Indeed I am planning to do charged particle simulations in a fluid flow ...

Can you please guide me on how to do that using the MHD module ...

I was able to load the module into FLUENT. Then, I defined a value for the voltage on two parallel walls where the flow is supposed to pass in between, but no good results were obtained. Actually, nothing at all happened (As if the module wasn't loaded/added). There were no effect on the charged particles ...

I am sure I did something wrong ...

Also, can you check the discussion in the following link (A post written by: vsmkrm298 mentioned something about solving a similar problem by solving the poissons equation for applied or induced potential: http://www.cfd-online.com/Forums/flu...ric-field.html

Your reply is highly appreciated ...

Thank you in advance ...

Kind regards

RGI · November 16, 2015, 03:40

Any one who can help?

LuckyTran · November 16, 2015, 10:38

Use the MHD module. It's already done for you. If you were to write your own udf, you would just end up remaking the MHD module (which is just a bunch of UDF's).

Did you remember to enable the MHD module after loading it?

RGI · November 16, 2015, 12:20

Hi ...

Sure, the MHD was enabled, but as I said: I was able to load/enable the module into FLUENT. Then, I defined a value for the voltage on two parallel walls where the flow is supposed to pass in between, but nothing at all happened (As if the module wasn't loaded/added). There were no effect on the charged ...

If you have any experience in using the MHD module or defining the UDFs, can you please provide/guide me through them ...

Thanks in advance ...

Rrgards

kcgmech · November 19, 2015, 00:08

how to enable MHD module in ANSYS Fluent 12 ?

sina_sls · March 5, 2022, 09:30

Quote:

Originally Posted by LuckyTran

Use the MHD module. It's already done for you. If you were to write your own udf, you would just end up remaking the MHD module (which is just a bunch of UDF's).

Did you remember to enable the MHD module after loading it?

Hello Lucky Tran,
I want to show Electric Field in Result, Did I use correct way for doing this? I attached the picture

Best Regards,

November 2, 2015, 05:01	Electric Field (UDF) - FLUENT	#1
RGI New Member A.A Join Date: Nov 2015 Posts: 6 Rep Power: 10	Good morning everyone ... I am doing a research using FLUENT, and I am trying to introduce an electric field to FLUENT through a UDF. The electric field is to be constant with a value that the user would define. I have read that one can do that by solving the poissons equation for applied or induced potential, where the derivative of the potential can be taken to get the electric field. Such thing can be done by defining a UDF that I am not fully aware of. I would appreciate it if someone can help in defining this UDF or if someone has an easier approach/way to define an electric field to FLUENT ... Please note that the built in module MHD does not suit my problem ... Thank you in advance ... Kind regards

November 19, 2015, 00:08		#8
kcgmech New Member Ganesh K C Join Date: Oct 2014 Location: Tiruchirappalli, India Posts: 29 Rep Power: 11	how to enable MHD module in ANSYS Fluent 12 ? __________________ -- K.C.Ganesh Research Scholar NIT Trichy India

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November 8, 2015, 03:10		#2
RGI New Member A.A Join Date: Nov 2015 Posts: 6 Rep Power: 10	Any one who can help?

November 9, 2015, 00:10		#3
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,665 Rep Power: 65	I would have recommended the MHD module as a start Can you elaborate on what you hope to accomplish by adding a constant electric field? If you want to define a constant electric field, it's like defining a constant scalar field or defining a global constant (like pi). This part is trivial and you do not need a poisson equation for it (it's constant everywhere). So what do you plan to do after? If you plan to do charged particle simulations in a fluid flow then you're back to to MHD.

November 13, 2015, 13:31		#4
RGI New Member A.A Join Date: Nov 2015 Posts: 6 Rep Power: 10	Hi ... Many thanks Mr. LuckyTran for your reply ... I really appreciate it ... Indeed I am planning to do charged particle simulations in a fluid flow ... Can you please guide me on how to do that using the MHD module ... I was able to load the module into FLUENT. Then, I defined a value for the voltage on two parallel walls where the flow is supposed to pass in between, but no good results were obtained. Actually, nothing at all happened (As if the module wasn't loaded/added). There were no effect on the charged particles ... I am sure I did something wrong ... Also, can you check the discussion in the following link (A post written by: vsmkrm298 mentioned something about solving a similar problem by solving the poissons equation for applied or induced potential: http://www.cfd-online.com/Forums/flu...ric-field.html Your reply is highly appreciated ... Thank you in advance ... Kind regards

November 16, 2015, 03:40		#5
RGI New Member A.A Join Date: Nov 2015 Posts: 6 Rep Power: 10	Any one who can help?

November 16, 2015, 10:38		#6
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,665 Rep Power: 65	Use the MHD module. It's already done for you. If you were to write your own udf, you would just end up remaking the MHD module (which is just a bunch of UDF's). Did you remember to enable the MHD module after loading it?

November 16, 2015, 12:20		#7
RGI New Member A.A Join Date: Nov 2015 Posts: 6 Rep Power: 10	Hi ... Sure, the MHD was enabled, but as I said: I was able to load/enable the module into FLUENT. Then, I defined a value for the voltage on two parallel walls where the flow is supposed to pass in between, but nothing at all happened (As if the module wasn't loaded/added). There were no effect on the charged ... If you have any experience in using the MHD module or defining the UDFs, can you please provide/guide me through them ... Thanks in advance ... Rrgards