Firstly, I apologize if this should go somewhere else, but I couldn't find a specific forum to post this.
I am about to conduct a CFD study on the Strouhal-Reynolds dependence for arrays of tubes.
I want to be thorough with this study, and I will perform a mesh-independence study of it. This means:
1) I will solve the problem with an initial mesh and I will obtain a solution
2) I will solve the same problem again with a finer mesh and compare
3) If the solutions were significantly different, I will proceed with an even finer mesh
4) Keep doing so until the solution does not change anymore (within some tolerance)
Now that I am going to start I've got some doubts about how much I should refine the mesh in each step to obtain meaningful changes.
For instance, let's define N as a parameter which may be, for instance, the number of faces in a given contour of the domain. Thus, the number of cells of the mesh will grow (in 2D) proportionally to N^2.
My question is: How much should I refine the mesh for each following step? Should I take 2*N (thus the number of cells will be multiplied by 4), 1.5*N,...? Or is it too much?
I'd like to make moderate steps in order not to waste too much computing resources (it is transient problem, the computing time grows waaay faster than N^2), but if the mesh is not much finer than the previous one, then the solution I will obtain will not differ from the previous one either... and then it might look like the problem got grid-independent, but actually it didn't. Therefore, smaller refinement ratios would require tougher tolerances.
So my question is... what tolerances/refinement ratios would you guys reccomend? Is there any relationship between refinement ratio and tolerances? What is your experience about this?
Thanks for answers!
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I am about to conduct a CFD study on the Strouhal-Reynolds dependence for arrays of tubes.
I want to be thorough with this study, and I will perform a mesh-independence study of it. This means:
1) I will solve the problem with an initial mesh and I will obtain a solution
2) I will solve the same problem again with a finer mesh and compare
3) If the solutions were significantly different, I will proceed with an even finer mesh
4) Keep doing so until the solution does not change anymore (within some tolerance)
Now that I am going to start I've got some doubts about how much I should refine the mesh in each step to obtain meaningful changes.
For instance, let's define N as a parameter which may be, for instance, the number of faces in a given contour of the domain. Thus, the number of cells of the mesh will grow (in 2D) proportionally to N^2.
My question is: How much should I refine the mesh for each following step? Should I take 2*N (thus the number of cells will be multiplied by 4), 1.5*N,...? Or is it too much?
I'd like to make moderate steps in order not to waste too much computing resources (it is transient problem, the computing time grows waaay faster than N^2), but if the mesh is not much finer than the previous one, then the solution I will obtain will not differ from the previous one either... and then it might look like the problem got grid-independent, but actually it didn't. Therefore, smaller refinement ratios would require tougher tolerances.
So my question is... what tolerances/refinement ratios would you guys reccomend? Is there any relationship between refinement ratio and tolerances? What is your experience about this?
Thanks for answers!
Germany vs France Live Stream Online 2014
Germany vs France Live Stream
Online 2014
Germany vs France Live Stream Online 2014
Brazil VS Colombia Live Stream Online 2014
Brazil VS Colombia Live Stream Online 2014
Brazil VS Colombia Live Stream Online 2014
Algeria vs Germany News
Colombia vs Brazil Live Stream Online 2014
FOUR FUN THINGS TO DO IN ESSEX COUNTY THIS CANADA DAY
Germany vs France Live Stream Online 2014
Germany vs France Live Stream Online 2014
Four fun things to do in Essex County this Canada Day
Colombia vs Brazil Live Stream Online 2014
Germany vs France Live Stream Online 2014
France VS Germany Live Stream Online 2014
Brazil VS Colombia Live Stream Online 2014
Kynard, Bingson Nab Title at USA
Kynard, Bingson Nab Title at USA
Brazil VS Colombia Live Stream Online 2014
France VS Germany Live Stream Online 2014