Quality Issue

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  • Last Post 19 October 2018
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Elfster85 posted this 14 October 2018

Hi,

So I'm trying to mesh my model C02 powered car in Ansys for a CFD simulation but it will only mesh successfully when the quality of the curve is very bad (as seen in the "no mesh error")..

When I try to decrease the element size I keep getting an error but the curve is actually of high quality  ( as seen in the section plane on "failed mesh").

 

Would really appreciate it if someone could help

Thank you

//Elvin Tiagi

Mesh settings:

 

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kkanade posted this 15 October 2018

Hi, 

As ANSYS employee, I am not allowed to download attachments. 

As per the images you have inserted, I can see a cut section of the mesh. But I can not see entire geometry or where mesh is failing. 

If you are getting error in meshing, please use right click on the message and use go to problematic geometry. It may give location of problematic geometry. You may want to modify geometry at this location in DM or SpaceClaim. At the same time, you can use virtual topology if required. You can use local edge or face sizing as well. 

Regards,

Keyur

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kkanade posted this 15 October 2018

Also you may want to look at 

https://caeai.com/resources/tips-tricks-hex-brick-meshing-ansys-e-learning

Regards,

Keyur

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Elfster85 posted this 15 October 2018

Hi,

Thanks for taking the time to reply! I've looked at the problematic geometry and it seems to be this:

I actually use Autodesk Fusion 360 for CAD and I import in the .step file into ansys. This is how the geometry looks like (highlighted is the part ansys gives an error for):

 

Do you think the hex meshing in the video will help me here or is it something else?

 

Thank you

//Elvin Tiagi

rwoolhou posted this 15 October 2018

Have you split/subtracted the car volume from the outer zone? It's hard to tell from the images. Assuming that's the case is a cm scale mesh fine enough to capture the details of the car? 

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Elfster85 posted this 15 October 2018

Yes, I have subtracted the car from the outer zone. I don't really get what you mean by cm scale mesh.

Thank You

//Elvin Tiagi

kkanade posted this 16 October 2018

Hello, 

The highlighted face may be the problem. From image it looks like it is a single curved surface. Can you please open geometry in SpaceClaim. Then split this face into more no. of faces, may be 3 or 4 faces. You can use Design -- Split command. Then check the geometry by selecting bodies in tree -- right click -- check geometry. 

Following videos may help you. 

Regards,

Keyur

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rwoolhou posted this 16 October 2018

If you read through the settings you've used the minimum cell size is 1cm: as I don't know how big your object is I was checking that was suitable. The CO2 powered cars I've seen run off a soda siphon cylinder so are typically 5-10cm long.  

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Elfster85 posted this 17 October 2018

Hi,

Its worked now! Thank you so much for helping me!

//Elvin Tiagi

kkanade posted this 19 October 2018

Glad that it worked out!

Regards,

Keyur

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