# Add the volumetric force source terms

**URL:** <https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476>\
**Category:** General\
**Created:** [11 September 2021 07:34 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476 "2021-09-11T07:34:21Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Edmund](https://avatars.discourse-cdn.com/v4/letter/e/439d5e/32.png) [@Edmund](https://pyfr.discourse.group/u/Edmund)\
**Post date:** [11 September 2021 07:34 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476/1 "2021-09-11T07:34:21Z")

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Hello All,

I tried to simulate the wind turbine wakes by actuator line method. But, how can I add the volumetric force source terms to N-S equations? And, where can I find and change the turbulent flows model in PyFR?

Thank you for your help.

Regards,  
Edmund

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**Author:** ![fdw](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@fdw](https://pyfr.discourse.group/u/fdw)\
**Post date:** [11 September 2021 14:21 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476/2 "2021-09-11T14:21:15Z")

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Source terms can be added using the `[solver-source-terms]` directive in the .ini file. Further details can be found in the user guide: [User Guide — Documentation](https://pyfr.readthedocs.io/en/latest/user_guide.html#solver-source-terms)

Being designed for ILES, PyFR does not make use of a turbulence model.

Regards, Freddie.

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**Author:** ![Edmund](https://avatars.discourse-cdn.com/v4/letter/e/439d5e/32.png) [@Edmund](https://pyfr.discourse.group/u/Edmund)\
**Post date:** [11 September 2021 15:11 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476/3 "2021-09-11T15:11:37Z")

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Hi Freddie,

Thank you for your rapid reply and help.

Regards,  
Edmund

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**Author:** ![Edmund](https://avatars.discourse-cdn.com/v4/letter/e/439d5e/32.png) [@Edmund](https://pyfr.discourse.group/u/Edmund)\
**Post date:** [15 September 2021 14:05 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476/4 "2021-09-15T14:05:23Z")

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Hi Freddie,

Sorry for bothering you again. When I imported .msh to PyFR, there is an error. In the 2D model, the KeyError is (x1,x2) and in the 3D model, the KeyError is (x1,x2,x3). Whether this represents the coordinates of the node? Do you have any idea about it?  
Thank you for your help again.

 ![errorphoto](https://global.discourse-cdn.com/free1/uploads/pyfr/original/1X/951b02d4be1bd1aee14dce76709e3bb56c01c0ae.png)

Regards,  
Edmund

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**Author:** ![fdw](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@fdw](https://pyfr.discourse.group/u/fdw)\
**Post date:** [15 September 2021 14:17 UTC](https://pyfr.discourse.group/t/add-the-volumetric-force-source-terms/476/5 "2021-09-15T14:17:34Z")

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This is indicative of a bad mesh file with either unpaired faces or incorrectly tagged boundaries.

Regards, Freddie.