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Dynamic Mesh: Remeshing doesn´t work properly

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Old   March 17, 2018, 15:22
Default Dynamic Mesh: Remeshing doesn´t work properly
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Hi guys,

I am currently learning about the dynamic mesh function in ANSYS Fluent and therefore I looked into this tutorial on youtube by CFD-Ninja:

https://www.youtube.com/watch?v=gq7zmrKVWkA

In this tutorial, a rigid ball dropping in water is modelled.

This worked quite fine so far. Then I decided to add a force in the negative y-direction in the udf file by adding the last line of the following properties of the ball:

prop[SDOF_MASS] = 667;
prop[SDOF_IXX] = 34.784;
prop[SDOF_IYY] = 34.784;
prop[SDOF_IZZ] = 34.784;
prop[SDOF_LOAD_F_Y] = -100;

Unfortunately, with the force pushing the ball down, the remeshing of the dynamic mesh due to the balls motion doesn´t work properly anymore, as I get left handed faces in my mesh very quickly. I attached two pictures of the mesh during the mesh motion preview, as well as one picture of my remeshing settings. For some reason, Fluent doesn´t remesh the cells, they just get more and more distorted as the ball moves down. Without the added Force and thus only the gravitational force pulling on the ball, the remeshing works fine.

Does anyone have some tips regarding this problem? I am quite a beginner with ANSYS, so any help/comment is appreciated.
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Old   June 6, 2018, 07:52
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Dr. Peyman Davvalo Khongar
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Moi!

I think you need to do this,

Go to dynamic mesh zone, create/Edit and select interior1 in Zone name. The type should be Deforming. In the method, activate smoothing and Remeshing. Use zone scale info for filling the parameters in min and max length scale and max skewness.

This should work.

Moikka,

Peyman
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Old   June 6, 2018, 10:05
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Enrique Pérez Heredia
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Hello,
I'm simulating the same scenario and I found that to avoid mesh problems you should enable the Region face option under the remeshing tab.

You should also do as peyman says and introduce the data of your previous mesh.

You may also benefit from setting the remeshing interval to 1 and/or refining your mesh if you are dealing with high velocity scenarios.

Good luck!
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Old   June 6, 2018, 17:01
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Marcin
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Hi,

I've got the same problem, described here:
FSI 2D - dynamic mesh

Above advices didn't help me.

@maccheese did you solve your problem?
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Old   June 7, 2018, 05:56
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Hi guys,


I didn´t succeed in solving this problem. Instead I used another approach on defining the motion of my structure, I ended up using a profile. Remeshing works this way...
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