Learning Forum

[cfd]

Hi there all, I'm trying to make an animation with pathlines to illustrate the flow of air/gas. I'm trying to achieve something like this

But i can't seem to find any useful tutorial or guide (in either manuals or tutorials). Does anyone here have experience in something like this? It should be possible right? Any help or tips in achieving something similar to this is to me a great help. Thanks

[Supreetha J]

Hello,
Kindly refer to AIC course on Post-processing - Post Processing in Ansys Fluent | Ansys Innovation Courses
You can create pathlines from Rake Surface for better flow visualization.
Thank you!

[cfd]

Hello Supreetha j,

Thank you for your reply. Unfortunetly this course you refer to doesn't provide information about animation.(I had searched for in it before as well) It is good for a static image! but i had hoped to learn how to animate the flow to a video file instead of the full pathline in a static image.

Thanks nevertheless for your time and effort.

[Sunil Lilhare]

Hello, you can make use of the pathlines option in Ansys Fluent to get the shown results. Pathlines can be released from existing surface or you can create new surface and release it from there. To release it from a line ahead of the object, you need to create the line using proper co-ordinates.

To know more about how to do this, please have a look at the Lesson 4 Part 2 video of the wonderful course on External Aerodynamic Analysis of an FSAE Car using Ansys CFD whose link is given below.

Post Processing of an FSAE Car Simulation| Ansys Innovation Courses

[cfd]

Dear Sunil Lihare,

Thank you for your reply! This video of Lesson 4 part 2 really shows how to use pathlines from the start of a surface. Unfortunetly it doesn't show how to animate the beautiful pathline animation between 0:48 and 0:55 seconds of the video. It is so close to what i'm trying to achieve. The pulse mode in pathlines shows really well how the airflow around the object goes. But for now i don't see an option to save this animation and produce a video file as shown as in 0:48-0:55 of lesson 4 part 2. Is there a post processing course on this? 

Thank you!

[Sunil Lilhare]

Hello, to save the animation of pathlines use Save Pulse Animation option. Make sure to enable Draw Mesh and select surfaces to display together with the pathlines.

To know more about this please have a look at the section 39.1.5.1 of the Ansys Fluent User Guide in the link given below.

39.1. Basic Graphics Generation (ansys.com)

[cfd]

Dear Sunil,

Unfortunetly i do not have access to this part of Ansys. As the company i work for has Ansys till the 2021 version. The Ansys Fluent User Guide of that version shows in 39.1.5.1 how animate a scene. This is something i have tried yet no save pulse animation option to me is visible. I'm only able to achieve a rotation around a static point in time of the object. Is this "Save Pulse Animation" option something that is only supported in the 2022 and/or 2023 version of Ansys fluent? 

Best Regards

[Rob]

If you're using a commercial licence you may also have support as part of the deal. As I can't check please can you contact your account manager? Some of the pathline features may be newer than 2021. 

[cfd]

Dear Rob,

I already spoke to him. Unfortunetly the support on that side has expired as well. I assume that the pathline save option is for newer versions of ansys past 2021. The only thing that weirds me out is the fact that the video i shared is ~6 years old i assume it was made in ansys fluent/post (CFD) and therefore possible to recreate this pathline animation in the ansys 2021 version. 

[Rob]

Ah, OK. I think CFD Post has that function. Fluent's post processing has been seeing a lot of work as it's moved from "useful" to "useful and pretty" over the last several years. As Fluent's been improved we've tended to not use CFD Post. 

[cfd]

I can see why CFD post becomes unnecessary once fluent is able to do what CFD post can do and more. I'll see and try making it work in CFD Post for now, but it seems its quite tricky to export pulse information from fluent to a file format that CFD post can understand. Its good that ansys has updated this feature in the newer versions of fluent. As one can tell i'm struggling with this part haha.

[Rob]

Yes, there's an older way to animate the pathlines in Fluent too. Look at the max steps for pathlines, and start tinkering. It worked in v6.x which is about the last time I tried it!

Ansys hat - given we've got 2024R1 out I'd seriously consider talking to the account team for resuming support & updates. 

[cfd]

Dear Rob,

Thank you for the tips. I'll start digging into it. To me currently talking to the account team is not possible due to budgetary reasons. Perhaps in the future that'd be possible but for me now unfortunetly it is not.