blockMeshDict in Sandia_LTS combustion/reactingFoam/RAS tutorial
 

I have a doubt on the blockMeshDict to define the geometry in the Sandia_LTS combustion/reactingFoam/RAS tutorial.

The blockMeshDict file is here: https://github.com/OpenFOAM/OpenFOAM.../blockMeshDict

My question is as follows:

The inletPilot faces is defined as (5 3 4 6) (line 110)

The second of the wallTube patches is defined as (10 11 9 8) (line 99)

On both faces the outward normal is in the negative z-direction. The nodes of both faces are traversed in opposite direction.

Why is this? Thx.

Hi Domenico,

From a quick look it seems that face's (5 3 4 6) normal is towards the negative z-direction whereas the one of face (10 11 9 8) is towards the positive z-direction. I hope I am not misreading the blockMeshDict.

Best,
Petros

Dear Petros,

Sincere thanks.

I fail however to understand why on face (10 11 9 8) the normal is towards the positive z-direction.

Could you pls. elaborate?

Greetings, Domenico.

Hi Domenico,

Sorry for being misunderstood. When I said that the normal of face (10 11 9 8) points in the positive direction I was refering to the one that matches the order in which its vertices are traversed in the tutorial. I agree that since face (10 11 9 8) belongs to block (8 10 11 9 17 19 20 18) I would traverse its vertices as (10 8 9 11).

I think I have encountered similar mis-orientated faces. If I remember correctly blockMesh gives a fatal error only when all faces of a block are pointing inwards.

The question is what really happens if one or two faces are pointing inwards and how that affects calculations. I am not sure about it so I hope some more experienced users can shed some light.

Best,
Petros

Dear Petros,

Thank you for sharing your thoughts.

It is wonderful to hear that my doubts on the issue are shared by you.

I will seek further support.

Thanks again, Domenico.