CFL output for each element (NekRS v25)

[Aerokaur]

Hi,
I am using NekRS v25, and would like to know if there is a function available to output the CFL at every mesh element ? I know there is a computeCFL( ) which outputs the "max CFL" on whole mesh. I am more interested in getting the CFL for every mesh element.
Thanks,
Sharan

[yslan]

I've done this before with previous version, which might still be a good starting point.
https://github.com/yslan/nekrsExamples/tree/master/hemi_elementFilter
NekRS' cfl kernel combines the reduction, so it only output elementwise max CFL.

An alternative way is to compute it in Nek5000 's userchk, then you can get pointwise value. Here is an Nek5000 example: https://github.com/yslan/nek-utils/tree/main/outpost-select/hemi_cfl

Both examples will only dump elements that has high CFL. You can drop the IO part if you only care about the numbers.

[Aerokaur]

Thanks @yslan . This is helpful.