Create Cylinder (HOLLOW NO MESH OR CAVITY) inside a Cuboid
 

hello foamers
i have an interesting problem to discuss with you all.
1. i am having a cuboid of 10 cmx 10 cmx 10cm...which i can easily make in blockmesh.
2. i have to create a cylinder which lies entirely inside the cuboid close to the bottom. its dia is 1 cm and length 6 cm so it lies inside the cuboid.
3.i have to give boundary condition to this cylinder surface. so its a wall here

how do i delete the mesh of this cylinder, the cylinder is not supposed to have mesh inside
how do i define a patch of cylindrical surface, so i can give bc in 0 folder

the issue is: i cannot do so using blockmesh which is very tiring and prone to mistakes

i am trying to use cell set by deleting the cells using cylinder to cell
and define a patch using cylinder to cell
but i don't know exactly how to write this procedure using toposet dict
please help me foamers
i really need to get this done

i'm so glad i did it...
however i ran into another minute issue
when i create the cylinder
the mesh around it is irregular and nott a perfect circle.
how ca i smooth these faces to get the smooth circle...not exactly..but how can i improve this??
collapse edges or what??
image is attached here

i tried more refinement but still the circumference of circle contues to be irregular
my conclusion is: it can't be done using refinement or toposet or blockmesh
only way is
use .stl file of cylinder inside a cuboid
next use snapphexmesh to get the job done
will keept his thread updated

Hi,

If you know there is going to be cylinder in your geometry, then you can use blockMesh to create a mesh that has a cylinder. That way you can avoid the issue with irregular cells.

Cheers,
Antimony

i know can be done using blockmesh. but there is a problem. to get a cylinder completely inside the cube. you have to create different regions and write their numbering and its a whole lot tedious. job and once you get your numbering wrong/mistype. blockmesh will kill you with flurry of errors.
i am thinking about using snappy hex mesh using .stl file
if u have any simple beginner tutorials using a cylinder, could you point me in that direction???

Hi, can you please explain how did you extract the mesh inside the cylinder from your general mesh?