Learning Forum

[vganore]

Hi Friends,

Modeling flapping mechanism in Fluent needs considerable effort and time since you are bringing flapping motion (needs motion UDF, good quality mesh, additional dynamic mesh setting, turbulence etc.). Many students are trying to solve such problems. So I am sharing following useful materials/information to get you started:

1. Generate good quality mesh around flapping region 

2. Refer this flapping door tutorial (files are attached):

Part 1 Problem setup and results: 

https://youtu.be/YhBYsz9f1sw

 

Part 2 (UDF and Dynamic mesh):

https://youtu.be/_K3IrvuxZBk

 

3. Flapping tube tutorial discussion: http://studentcommunity.ansys.com/thread/dynamic-meshing-of-bending-tube/?postbadges=true

 

4. Here is my blog on similar flapping wing: http://www.ansys-blog.com/dragonfly-flapping-ansys/

https://www.youtube.com/watch?v=72nfgtUHnFc

[wbmckinney]

What version of Microsoft Visual Studio would you recommend installing to compile the UDF? I was trying to install VS Express 2012 but cannot find it available anywhere. Please let me know your thoughts.

Thanks,

Will McKinney

[vganore]

This information is available in ANSYS Fluent manual for respective ANSYS versions. 

2012 VS Express + VS SDK is available here: https://www.visualstudio.com/vs/older-downloads/

If you are using latest ANSYS products 18.0 and above, you could go ahead with latest 2017 VS Community. 

[ankushcool288]

I followed your tutorial step by step but some error is popping up and I quote "the udf library you are trying to load is not compiled for 2ddp on the current platform(win64)".

Please explain to me how can I remove this error.

 

[vganore]

May I know how are you launching Fluent?? Are you using VS compiler and MS SDK? If possible, please share your project file achieve (.wbpz).

[ankushcool288]

I am happy to tell you that I have removed my errors with the help of my friend. Your tutorial helps me a lot and I want to explore more about it. Please keep sharing.

Thank you

[wbmckinney]

I am having issues with my model for the flapping tube. Vishal, you recommended to not have a thickness on the tube. However, I am having trouble inputting the tip region of the tube as a wall BC instead of an interface BC. Right now I have 2 separate parts in my model: the atmosphere and the tube. Also, I get an error when I try to run the dynamic mesh saying negative cell volume. Please let me know if you have any suggestions.

Regards,

Will McKinney

[Raef.Kobeissi]

Nice tutorial!

[jaiswal.3]

Hi Ankush

I am also facing the same problem you have faced.Can you help me to remove this error out? Any help from your side will be really helpful

[jaiswal.3]

Hi Vishal,

Nice Tutorial.I am also working in the area of hydrodynamics of oscillations.Please guide me, how to start with UDFs and what are the prerequisites,like software compatibility and what are the necessary steps before compiling the UDFs.I have tried your tutorial and facing the error like "The UDF library you are trying to load is not compiled for 2D on the current platform.The system cannot find the file specified." 

Please Help

Thanks

Manish 

[vganore]

Manish, Can you provide following details?

1. Which Microsoft compiler are you using?

2. Which version of ANSYS?

3. How are you launching Fluent? Through workbench or standalone mode or through MS SDK command prompt?

Files (including UDF and fluent case) are attached above which you can take and test. My understanding is you have a compiler issue. 

 

 

[jaiswal.3]

Thanks Vishal,

The microsoft compiler which I am using is Visual studio 2010

I am using ANSYS '13'

I am launching Fluent through Workbench,

I also think that there is a compiler issue, how to fix that.

[mahdishuvo]

 Vishal,

Thanks for the tutorial. I have followed the similar equations and UDF but the motion of the body is not harmonic. the body is rotating around the center of rotation. What could be the possible reason? I can share .wbpz file if you want.

Thanks.

[mahdishuvo]

My default time step was 1. If i make the time step to 0.1, it oscillates nicely. I don't actually get why this happens. Can any of you give me some ideas?

[Amine Ben Hadj Ali]

Pretty tutorials

 

[Karthik Remella]

Vishal,

This is an excellent tutorial. 

Thanks.

Best Regards,

Karthik

[psalmsyst]

Thanks for this tutorial.
However, I will like to know what part of the code Is responsible for the fixed end. What if I want the right end to be fixed while the other end flaps?
I have a similar project but my door is vertical. Will like to know how to make either ends fixed

[vganore]

Define the center of gravity location that we specify in Dynamic mesh zone in Fluent panel. The code only defines the motion of the rigid body. 

[Philipmorris]

 

Excuse me, May i ask you about the udf. I 'm simulate 2D unsteady pitching of rectangular plate. The motion of the rectangular plate in cross-flow y direction is expressed by

My question , Can i used your UDF but change COS to SIN.

Thanks for your kindness

[Shuvadeep]

 @vganore

In the tutorial above, where is the origin. Is it at the plate center or at the hinged point?

[sarvapriyasingh]

could you please help me out in the same error what you were getting ?

[rexfoxoloughlin]

I'm getting the same errors, did you figure it out?n

[Mohammad Reza Soufivand]

Is it possible to access the mesh and UDF files of this simulation? I didn't see any attached files or download link.

[satyam]

Hello, I am trying to simulate the effet of trailing edge flap. I have created a udf based on cg motion but i am facing problems. The rotor has 4 zones, 3 zones each containing the trailing edge flaps for each blade (three blades) and one zone containing the remaining. I am rotating the main domain Zone1 with all the blades with sliding mesh method and all other zones are rotating relative to the first zone. So far no problems. Now as the domain with blades is rotating along z-axis (0,0,1), At the same time I want to flap the trailing edge with a function lets say sin theta degrees where theta is azimuthal. when the blade is between 180 and 360 degrees, i want the trailing edge to flap with function A 
I m using the dynamic mesh method with a rigid body and the trailing edge is not deforming. initially, i am giving the cg points x and y as the point about which the trailing edge will flap for each blade and hooking the udf in the dynamic mesh.

[Rob]

Given you also asked here /forum/forums/topic/udf-for-flapping-of-the-aifoil/ I'll lock this thread.