[Yann]

So... you created a new mesh, right?

[Amirthaa]

No.. I'm not getting what I'm missing to understand

[Yann]

Originally Posted by Amirthaa

I have changed the position of geometry inside the mesh

What do you mean by this? What did you concretely do to move the position of your geometry in your mesh?

[Amirthaa]

I essentially used sketchup to create my geometry. So I moved the geometry to my new required position in sketchup and saved it in stl format. Then, I replaced this file for geometry in place of the older one.

[Yann]

and you ran blockMesh and/or snappyHexMesh?

[Amirthaa]

Yes.. I ran for a trial

[Yann]

Then you changed you mesh!

You moved your geometry and re-run snappy = you generated a new mesh, and you will need to map the results from the old mesh to the new mesh if you want to use the previous results to start your new simulation.

For your own sake, please be more specific about what you have done when posting on the forum: details matter!
It took 9 messages to get from "I have not made any changes to the mesh" to "I modified the position of my geometry, created a new stl, and re-run snappy on this new stl".
I've been pretty insistent because it's a simple issue and I was pretty sure you did modify the mesh. On a more complex issue I would probably have failed to help you if you didn't provide detailed information about the changes you have made to your case.

Cheers,
Yann

[Amirthaa]

Alright. Since I'm a beginner to OpenFOAM, I'm still learning of what details would be essential for a doubt I post. I shall keep in mind to add necessary details in my upcoming posts.
Thanks for taking your time to help out.

[Yann]

Sure, no worry, everyone has been a beginner.
And when it comes to CFD and OpenFOAM, everyone keeps learning, for a very long time, not to say a lifetime!

But this is exactly because you are a beginner that you need to give detailed information about what you have done. A very small problem (a typo, wrong command, proper command but wrong order, missing option...) can lead to an error so you need to provide all information (what you've done, what exact command you've typed, what error message you got) so someone with more experience can spot what is wrong and help you to solve it.

On a case like your last error, this would be a detailed description of the changes you made between the case which is running and the one where you get the error:

1. Modify geometry position
2. Create new STL
3. Replace old STL by the new one in the case which already ran
4. BlockMesh (exact command you ran)
5. SnappyHexMesh (exact command you ran)
6. SimpleFoam (exact command you ran) => I get this error

Every information on this list is important to understand where it gets wrong.

Have fun Foaming!
Yann

[Amirthaa]

I shall keep a note of that.