Selecting certain faces for rotating elements

Danmeal · November 3, 2023, 05:17

Hi,

Currently trying to set up a simulation for a car with rotating wheels. I've made my mesh with cfMesh, with 7 distinct patches - those being the external boundaries and the car itself.

I'd like to apply rotating velocity patches to just the wheels as a starting step, however I'm unsure how to specifically choose the wheels to apply this patch to as they're part of the entire car patch itself.

Does anyone know how to extract the wheels only to apply the rotating velocity to them?

Yann · November 3, 2023, 05:49

Hello Daniel,

The easiest way would be to separate the wheels from the car from scratch before meshing so you can separate patches for the wheels and car body.

If you cannot, the other solution is to use topoSet + createPatch to select wheels and create new patches, but this is a bit tedious to setup.

Yann

Danmeal · November 3, 2023, 05:57

Hi Yann,

How would the first option work more specifically? Would I split the wheels from the car and mesh them separately and combine them somehow?

Yann · November 3, 2023, 06:18

I'm not very familiar with cfMesh, but don't you provide a single STL file containing your object and domain boundaries?

If this is right, then you would just need to define additional patches for the wheels in your STL file rather than having it as one single patch with the car.

Danmeal · November 3, 2023, 09:35

Yeah pretty much so I've made my geometry in AutoCAD and exported it as an STL file (without the domain boundaries). I then generate the domain and convert the STL file into an FMS file which cfMesh needs. Finally I use cfMesh's catesianMesh command where it actually meshes and sets the patches.

This is where I am stuck because when the mesh is made it defines the boundaries like xMax, xMin, etc, which are then renamed after to inlet/outlet/etc. I'm just unsure how to name the wheels specifically.

November 3, 2023, 05:17	Selecting certain faces for rotating elements	#1
Danmeal New Member Daniel Join Date: Sep 2023 Posts: 5 Rep Power: 2	Hi, Currently trying to set up a simulation for a car with rotating wheels. I've made my mesh with cfMesh, with 7 distinct patches - those being the external boundaries and the car itself. I'd like to apply rotating velocity patches to just the wheels as a starting step, however I'm unsure how to specifically choose the wheels to apply this patch to as they're part of the entire car patch itself. Does anyone know how to extract the wheels only to apply the rotating velocity to them?

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November 3, 2023, 05:49		#2
Yann Senior Member Yann Join Date: Apr 2012 Location: France Posts: 1,068 Rep Power: 26	Hello Daniel, The easiest way would be to separate the wheels from the car from scratch before meshing so you can separate patches for the wheels and car body. If you cannot, the other solution is to use topoSet + createPatch to select wheels and create new patches, but this is a bit tedious to setup. Yann

November 3, 2023, 05:57		#3
Danmeal New Member Daniel Join Date: Sep 2023 Posts: 5 Rep Power: 2	Hi Yann, How would the first option work more specifically? Would I split the wheels from the car and mesh them separately and combine them somehow?

November 3, 2023, 06:18		#4
Yann Senior Member Yann Join Date: Apr 2012 Location: France Posts: 1,068 Rep Power: 26	I'm not very familiar with cfMesh, but don't you provide a single STL file containing your object and domain boundaries? If this is right, then you would just need to define additional patches for the wheels in your STL file rather than having it as one single patch with the car.

November 3, 2023, 09:35		#5
Danmeal New Member Daniel Join Date: Sep 2023 Posts: 5 Rep Power: 2	Yeah pretty much so I've made my geometry in AutoCAD and exported it as an STL file (without the domain boundaries). I then generate the domain and convert the STL file into an FMS file which cfMesh needs. Finally I use cfMesh's catesianMesh command where it actually meshes and sets the patches. This is where I am stuck because when the mesh is made it defines the boundaries like xMax, xMin, etc, which are then renamed after to inlet/outlet/etc. I'm just unsure how to name the wheels specifically.