Hi Aziz and Franco,

Thank you for your replies. I contact with Ansys support center in Australia and they told me the derivatives in CFD-post and Fluent are different. I copy their respond here and it may help other guys  if they have the same problem.

Regards,

Siamak 

----------------------------------------------------------------------------------------------------------------

Hi Siamak, 

The confusion you are encountering is completely understandable as the definitions behind each code’s gradient functions do in fact change between codes. If you consult section 7.15.9 “Fluent Files” under the “Differences between CFD Post and Fluent” section in the CFD-Post Help Guide there is an explanation as to why you are experiencing these differing gradient solutions between Post and Fluent. I have quoted this below for your ease of reading.

“There may be substantial differences between gradients calculated in the Fluent solver and gradients calculated in CFD-Post. The Fluent solver uses options such as boundary treatments and limiters to calculate gradients; CFD-Post calculates gradients independently of the Fluent solver, and does not have access to all of the same data.”

So in other words, the values you achieve in Fluent will be different than the ones in Post. Ideally, the values you are seeing in Fluent will be more reliable that the ones seen in Post as the data is being pulled directly from the code and has access to the entire data set . If you do want to continue working within Post; I would recommend exporting the gradients you achieve in Fluent as a Variable, and then importing/loading these into Post. If you do wish to export the data from Fluent, section 3.17 in the help guide will help you to export and load those variables into Post.

I hope this helps with any confusion you are having!

Regards,

Mitch  

Look here.

http://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDsQFjACahUKEwjhvIvKor_IAhWIa3IKHYKTAOM&url=http%3A%2F%2Fwww.researchgate.net%2Ffile.PostFileLoader.html%3Fid%3D55e6bb885cd9e30dfa8b4577%26key%3D1a24caae-2598-403e-b49c-183f465f4c31%26assetKey%3DAS%253A273844202344453%25401442300953682&usg=AFQjCNHtpAD0kCvZLWtLGxx_eqRSHBtaDA&bvm=bv.104819420,d.bGQ

Franco

Hi Aziz and Franco,

Thank you for your replies. I contact with Ansys support center in Australia and they told me the derivatives in CFD-post and Fluent are different. I copy their respond here and it may help other guys  if they have the same problem.

Regards,

Siamak 

----------------------------------------------------------------------------------------------------------------

Hi Siamak, 

The confusion you are encountering is completely understandable as the definitions behind each code’s gradient functions do in fact change between codes. If you consult section 7.15.9 “Fluent Files” under the “Differences between CFD Post and Fluent” section in the CFD-Post Help Guide there is an explanation as to why you are experiencing these differing gradient solutions between Post and Fluent. I have quoted this below for your ease of reading.

“There may be substantial differences between gradients calculated in the Fluent solver and gradients calculated in CFD-Post. The Fluent solver uses options such as boundary treatments and limiters to calculate gradients; CFD-Post calculates gradients independently of the Fluent solver, and does not have access to all of the same data.”

So in other words, the values you achieve in Fluent will be different than the ones in Post. Ideally, the values you are seeing in Fluent will be more reliable that the ones seen in Post as the data is being pulled directly from the code and has access to the entire data set . If you do want to continue working within Post; I would recommend exporting the gradients you achieve in Fluent as a Variable, and then importing/loading these into Post. If you do wish to export the data from Fluent, section 3.17 in the help guide will help you to export and load those variables into Post.

I hope this helps with any confusion you are having!

Regards,

Mitch  

Hi Siamak

I found the question and the following conversation very helpful. Just I was wondering how I should export the data from Fluent to CFD post. I'm using Fluent 16 and I couldn't find any "Export to CFD post" dialog box under the File tab. Any suggestion?

Zeinab

Hi Zeinab,

I usually use the workbench and input everything all together in one single file, which it can be more convenient to control all of your works in one integrated environment as well as access data easily. However, if you use the fluent itself, data will be saved automatically based on your settings. For example, if the simulation is transient, the frequency of saving data as well as output desirable parameters can be changed by “calculation activity” tab in the Fluent. After completion of the simulation, or even in the middle of the simulation after saving a couple of steps!, open CFD-POST and follow this route:

File/load results (change the file types to fluent)/ and select your results from the folder

If your simulation is transient, you can select the last time step result (select *.dat file). In this case, all previous time steps will be also loaded automatically. Time step can be changed from timestep selector.

Hope will be helpful, otherwise, let me know if you have further questions or concerns

Regards,

Siamak