edge sizing control--Calculate cell-to-cell expansion rate from bias factor
 

Hi Everyone,

could someone tell me how to calculate first cell height and cell-to-cell growth rate from bias factor and number of cells?

It would be very important. Anyway why does the Workbench Mesher use this kind of sizing (with bias factor) on the edges? Cell height and growth rate of successive cells is more useful IMO.

Thanks for the answer in advance!

ohh I got it
 

I figured it out...

Using the following notations:

Edge length L
Number of cells n
Total expansion ratio r (=bias factor in Ansys Meshing)
Cell-to-cell expansion k (or geometric growth ratio)
Start cell size ds
End cell size de

The equations to be fulfilled:
L=sum(ds*k^i), i=0..n-1
de/ds=r=k^(n-1)

From the above 3 equations any 3 of the 6 unknown mesh parameters can be calculated.

See this thread too where a guy made a code to carry out the calculations for any known-unknown combinations of the 6 parameters.
http://www.cfd-online.com/Forums/ope...alculator.html

Can you explain it in more detail

Thanks to 'la7low'

Hi

This doesn't work at least in 2019 R2 version. Does anyone know how to calculate it properly?

Thank you

@eansgo, the formulas given above work just fine for 2019 R3 version. I have implemented them in a matlab file. That might be helpful for people in the future.

Thanks.
This work of yours helped a lot.