[kandelabr]

Hello.
I've been using Python and jinja2 to calculate points and create blockMeshDict files with it.
I've shared the script with a few examples here: https://github.com/damogranlabs/classyBlocks
https://damogranlabs.com/2020/02/cla...for-blockmesh/

So far it proved useful to me. Feel free to use it, any comments and suggestions are most welcome.

Thanks!

[kandelabr]

Just a bump, I made some massive updates to mentioned scripts. Now you can (almost) easily create pipings, revolved (rotational) geometry, axisymmetric - wedge meshes etc. etc. etc.

In some cases blockMesh is better than snappy or anything else:

• you have absolute control of every cell
• you can easily script geometry parametrically
• it's very fast
• it's simple if you don't write blockMeshDict directly

I'd be happy to improve or add features! Have fun!
https://github.com/damogranlabs/classy_blocks

[wo315]

That's wonderful works!
Thank you very much

[kandelabr]

glad to hear that. there's another update coming soon, with some more goodies.
if anyone did actually ever use this, i'd be happy to get some feedback - where the problems are, what to improve, what to add.

[wo315]

Originally Posted by kandelabr

glad to hear that. there's another update coming soon, with some more goodies.
if anyone did actually ever use this, i'd be happy to get some feedback - where the problems are, what to improve, what to add.

Hi Nejc



I want to generate more than 100 cases. I think I can use some scripts. so I find you work. It's great. Thank you!



But I am a newbie about OpenFOAM and parametric design.


I want to put the solid in a 4.575m * 0.313 m numerical wave tank. I divided the domain to water and air.

1. the water height is change from 0.143 to 0.071. I want to use 0.001m * 0.001m per cell.
2. the solid will up the still water level or submerge in the water.



Can you give me some advice, how to use your tool to generate mesh like this? It's 2D cases.


If I want to use turbulence model, like kOmegaSST, how to handle the meshes?



Thank you very much
best regards.
Yang Wang

[kandelabr]

If I understood you correctly, this is the solid immersed in water. In that case your blocking would be something like the sketch in the attachment.

Create a function that creates the darker blue blocks on a specified position. Then just call it n-times with a for loop to generate other light blue parts. The same goes for the darker green blocks.

k-Omega SST could work with or without boundary layers so it depends on your flow conditions. in case you'll need resolved boundary layer (y+ < 1) that will complicate the mesh; I guess the simplest for you would be to use blockMesh just to generate geometry and use cartesian2DMesh from cfMesh to create the actual mesh for you: https://damogranlabs.com/2020/10/blo...xternal-flows/ . In that case the blocking gets much simpler - create a single block for outer domain, get STL from that, then another blockMesh for the 'white' wall parts for from the sketch and extract those, then combine to a single STL. See chapter 2.2 in this manual: http://cfmesh.com/wp-content/uploads...fMesh_v1.1.pdf

You'll find everything else in the simpleFoam/pitzDaily tutorial.

[wo315]

Originally Posted by kandelabr

If I understood you correctly, this is the solid immersed in water. In that case your blocking would be something like the sketch in the attachment.

Create a function that creates the darker blue blocks on a specified position. Then just call it n-times with a for loop to generate other light blue parts. The same goes for the darker green blocks.

k-Omega SST could work with or without boundary layers so it depends on your flow conditions. in case you'll need resolved boundary layer (y+ < 1) that will complicate the mesh; I guess the simplest for you would be to use blockMesh just to generate geometry and use cartesian2DMesh from cfMesh to create the actual mesh for you: https://damogranlabs.com/2020/10/blo...xternal-flows/ . In that case the blocking gets much simpler - create a single block for outer domain, get STL from that, then another blockMesh for the 'white' wall parts for from the sketch and extract those, then combine to a single STL. See chapter 2.2 in this manual: http://cfmesh.com/wp-content/uploads...fMesh_v1.1.pdf

You'll find everything else in the simpleFoam/pitzDaily tutorial.

Thank you reply.


I will try to follow your advice. I am modifying your airfoil_2d case that's the only example I think is same my case.



but I think if I use your tools, I needn't to use cfMesh or snappyHexMesh to generate boundary layer. I can refine the near wall region use expansion ratio to 1.2 or some other value and let's the yPlus < 1. If the yPlus > 30, the first boundary layer thickness is greater than the yPlus < 1. But the total boundary layer total thickness has some different? Can you tell me ?


Thank you very much!
Best regards
Yang Wang

[wo315]

Originally Posted by kandelabr

If I understood you correctly, this is the solid immersed in water. In that case your blocking would be something like the sketch in the attachment.

Create a function that creates the darker blue blocks on a specified position. Then just call it n-times with a for loop to generate other light blue parts. The same goes for the darker green blocks.

k-Omega SST could work with or without boundary layers so it depends on your flow conditions. in case you'll need resolved boundary layer (y+ < 1) that will complicate the mesh; I guess the simplest for you would be to use blockMesh just to generate geometry and use cartesian2DMesh from cfMesh to create the actual mesh for you: https://damogranlabs.com/2020/10/blo...xternal-flows/ . In that case the blocking gets much simpler - create a single block for outer domain, get STL from that, then another blockMesh for the 'white' wall parts for from the sketch and extract those, then combine to a single STL. See chapter 2.2 in this manual: http://cfmesh.com/wp-content/uploads...fMesh_v1.1.pdf

You'll find everything else in the simpleFoam/pitzDaily tutorial.

I just read the linke you give me.


1. I can not find anything about two main script. “./generate_mode.py and ./generate_domain.py"
2. but the link has another link, maybe can solve my probel I will read it and get it.


Is it right?
Thank you

Yang Wang

[kandelabr]

you must write your own scripts for your geometry.
the next article is a more specific example but you'll still need your own classy_blocks scripts:

https://damogranlabs.com/2020/10/a-p...ne-from-pipes/

[wo315]

Originally Posted by kandelabr

you must write your own scripts for your geometry.
the next article is a more specific example but you'll still need your own classy_blocks scripts:

https://damogranlabs.com/2020/10/a-p...ne-from-pipes/

Thank you.


I am reading you blog paper now. I almost know you thinking.



Yang Wang

[wo315]

Originally Posted by kandelabr

you must write your own scripts for your geometry.
the next article is a more specific example but you'll still need your own classy_blocks scripts:

https://damogranlabs.com/2020/10/a-p...ne-from-pipes/

Hi, Nejc


I almost finished the procedure you told me how to generate hex mesh.


Thank you very much!


I need read your tutorials and code more time.


Maybe I will ask you more questions, please give me more advices. Thank you


Yang Wang

[kandelabr]

yaay, you did it! =D

[dlahaye]

Thank you for making your wonderful code available!

Apologies for being impatient and only poorly acquainted with Python as programming environment.

How do I make sure that modules defined by classy_blocks get loaded prior to running the examples?

Edit: when running an example (e.g. "python from_points.py"), I get the error ModuleNotFoundError: No module named 'classy_blocks'. I have not been able to find where this module is defined.

Thanks! Domenico Lahaye.

[kandelabr]

this has been updated just yesterday - it's quite an overhaul.
see this repository: https://github.com/damogranlabs/classy_examples
and try to keep roughly the same directory structure as the examples repository.

good luck!

EDIT: the examples are made to be run via run.py where they are imported from respective directories - uncomment the "from_points" line in run.py and run that.

[dlahaye]

Sincere thanks for getting in touch!

My sincere apologies for being as slow as an old lame snake in my understanding.

Below is what I tried. Further guidance is much appreciated.

Here is what I did

1/ Downloaded both classy_blocks-master and classy_examples-main

djplahaye@Djps-MBP mypython % ls
classy_blocks-master classy_examples-main

2/ Set PYTHONPATH and verify its setting

export PYTHONPATH=/Users/djplahaye/mysoftware/mypython/classy_blocks-master/classes

ls $PYTHONPATH
__init__.py block.py mesh.py operations.py primitives.py shapes.py


3/ cd into classy_examples-main, uncomment import examples.primitive.from_points and run the script run.py

djplahaye@Djps-MBP classy_examples-main % ls
LICENSE README.md case classy_blocks examples run.py tests

djplahaye@Djps-MBP classy_examples-main % python run.py
Traceback (most recent call last):
File "run.py", line 7, in <module>
import examples.primitive.from_points
File "/Users/djplahaye/mysoftware/mypython/classy_examples-main/examples/primitive/from_points.py", line 1, in <module>
from classy_blocks.classes.primitives import Edge
ModuleNotFoundError: No module named 'classy_blocks.classes'

[kandelabr]

You don't have to add anything to path. Just rename classy_blocks-master to classy_blocks and put them into your working directory. For instance, your home folder:

~/example/
    classy_blocks/
    case/
    custom_modules/
    run.py

you MUST execute run.py where you import classy_blocks, see how the classy_examples is made.

[dlahaye]

Thx! Something is starting to work. Need to look further into it.

[dlahaye]

Greetings,

Question: revolve with angle equal to 180 degrees or larger does not work, correct? This has to do with face orientation, correct?

Edit: I would like to revolve over 360 (full circle) degrees? How do I concatenate 4 revolves each over 90 degrees taking as base the result of the previous operation? How do i merge pairs at the end?

Edit again: found cylinder as building block. Will look into this first. Thx!

Thanks, Domenico.

[dlahaye]

Greetings again.

The function set_axial_cell_size() allows to grade the mesh of a Cylinder object in axial direction.

The same function does not work for a RevolvedRing object as this object has no 'core' attribute.

How to you suggest to grade the mesh of a RevolvedRing object?

Thanks so much again. Domenico.

[kandelabr]

Hello,

that's a bug. It's fixed in the latest update.

Also please note I've renamed those functions with a more descriptive names:
- count_to_size_*() sets number of cells
- grade_to_size_*() keeps cell number and sets grading.
See the examples repository.

Thanks for the comment.