# Flow Region Set Up not working

**URL:** <https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573>\
**Category:** Project Support\
**Created:** [December 5, 2025, 7:52pm UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573 "2025-12-05T19:52:34Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![peregrineracing](https://www.simscale.com/forum/letter_avatar/peregrineracing/32/5_5575768a8748004e209b776fc1b2916d.png) [@peregrineracing](https://www.simscale.com/forum/u/peregrineracing)\
**Post date:** [December 5, 2025, 7:52pm UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573/1 "2025-12-05T19:52:34Z")

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Hi,

We are trying to create a simulation for our f1 in schools car. We had the same flow region set up for every other test but it isnt working on this one. We imported the model from an onshape assembly. [stemcar | SimScale Workbench](https://www.simscale.com/workbench/?pid=1341927851740782497&dcs=4933355a-c67f-434e-a074-ce7d45c30e95)

 ![image](https://www.simscale.com/forum/uploads/default/original/3X/6/c/6cb66838d970e5da159ff84f5be2205bb3135e33.png)

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**Author:** ![Ricardopg](https://www.simscale.com/forum/user_avatar/www.simscale.com/ricardopg/32/26909_2.png) [@Ricardopg](https://www.simscale.com/forum/u/Ricardopg)\
**Post date:** [December 6, 2025, 9:48pm UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573/2 "2025-12-06T21:48:16Z")

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Hi,

Quick suggestion: create the flow region first and then split the geometry - this should work.

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<div class="post-metadata">

**Author:** ![peregrineracing](https://www.simscale.com/forum/letter_avatar/peregrineracing/32/5_5575768a8748004e209b776fc1b2916d.png) [@peregrineracing](https://www.simscale.com/forum/u/peregrineracing)\
**Post date:** [December 7, 2025, 10:43am UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573/3 "2025-12-07T10:43:00Z")

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Hi, we’ve done that but t still does not work. Any other suggestions?

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<div class="post-metadata">

**Author:** ![Ricardopg](https://www.simscale.com/forum/user_avatar/www.simscale.com/ricardopg/32/26909_2.png) [@Ricardopg](https://www.simscale.com/forum/u/Ricardopg)\
**Post date:** [December 7, 2025, 10:50am UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573/4 "2025-12-07T10:50:19Z")

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Hi, my suggestion was to create the _full_ flow region first, and then split it.

 ![image](https://www.simscale.com/forum/uploads/default/original/3X/d/1/d12117fcd7f6c88ce0914f03e9e4b88dbd3587a3.png)

 ![image](https://www.simscale.com/forum/uploads/default/original/3X/4/6/461ea96ac2f51aaed42648f416b193c522920737.png)

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<div class="post-metadata">

**Author:** ![peregrineracing](https://www.simscale.com/forum/letter_avatar/peregrineracing/32/5_5575768a8748004e209b776fc1b2916d.png) [@peregrineracing](https://www.simscale.com/forum/u/peregrineracing)\
**Post date:** [December 8, 2025, 10:48am UTC](https://www.simscale.com/forum/t/flow-region-set-up-not-working/100573/5 "2025-12-08T10:48:33Z")

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Thanks, this has worked