|
[Sponsors] |
February 28, 2013, 11:19 |
Grid refinement ratio for unstructured mesh
|
#1 |
Senior Member
OJ
Join Date: Apr 2012
Location: United Kindom
Posts: 473
Rep Power: 20 |
Hello,
I am trying to streamline the mesh independence practices using Grid Convergence Index and Richardson Extrapolation as they are considered the best in practical CFD. (Ref: Roache, P. J. "Perspective: a method for uniform reporting of grid refinement studies." TRANSACTIONS-AMERICAN SOCIETY OF MECHANICAL ENGINEERS JOURNAL OF FLUIDS ENGINEERING 116 (1994): 405-405.) Now, element sizes for the consecutive meshes should be known to get the grid refinement ratio used in the calculations in this procedure. But since we use unstructured mesh along with the extruded mesh; I am not sure if the value of element local element size (in the important regions of high gradients) is representative of the size for that particular mesh. Roache suggests the following formula for grid refinement ratio for unstructured meshes, using their element-counts and : Now, he defines D as Dimensionality. What does it mean and how to calculate it from the fluid domain?? Thanks OJ Last edited by oj.bulmer; March 4, 2013 at 10:18. Reason: Correction in formula of r |
|
March 4, 2013, 04:10 |
|
#2 |
Senior Member
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26 |
D = 1 for a one-dimensional case.
D = 2 for a two-dimensional case. D = 3 for a three-dimensional case.
__________________
The skeleton ran out of shampoo in the shower. |
|
March 4, 2013, 04:17 |
|
#3 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,399
Rep Power: 46 |
The idea behind it is that if you want cells with half the edge length in a 3D domain, you need 2^3 times as many cells...
|
|
March 4, 2013, 10:15 |
|
#4 |
Senior Member
François Grégoire
Join Date: Jan 2010
Location: Canada
Posts: 392
Rep Power: 17 |
||
March 4, 2013, 10:18 |
|
#5 |
Senior Member
OJ
Join Date: Apr 2012
Location: United Kindom
Posts: 473
Rep Power: 20 |
macfly, thanks. Corrected.
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
how to set periodic boundary conditions | Ganesh | FLUENT | 15 | November 18, 2020 06:09 |
[snappyHexMesh] Weird snapping outside a refinement region | jasimpson89 | OpenFOAM Meshing & Mesh Conversion | 0 | July 29, 2012 20:46 |
[snappyHexMesh] Boundary layer in a pipe | Clementhuon | OpenFOAM Meshing & Mesh Conversion | 6 | March 12, 2012 12:41 |
pressure eq. "converges" after few time steps | maddalena | OpenFOAM Running, Solving & CFD | 69 | July 21, 2011 07:42 |
How to control Minximum mesh space? | hung | FLUENT | 7 | April 18, 2005 09:38 |