Re: [Nek5000-users] DNS of turbChannel
The turbChannel example is using a high pass filter relaxation term as SGS. For a DNS just - set lx1=8 and lxd=12 in SIZE - generate a finer mesh with more elements using genbox (if you change the mesh make sure to delete the old amg files) - set filtering=no in par -----Original message-----
From:[email protected] <[email protected]> Sent: Friday 9th February 2018 20:32 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
Hello Paul, Thank you a lot for your explanation; it really helps. For now, I am using the most recent turChannel example of NEK5000 V.17. I successfully simulated a turbulent channel with a Retau of 180 using 1536 elements (I am aware of its a lot of elements). The default settings were applied. I wonder is it in the .par file where you do the modification to convert it into DNS? Or somewhere else as well? Again, thank you for the help, Emily _______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
does "filtering=no" turn off the filtering completely? As far as I understand, even for DNS* some low amounts of filtering is needed (1% or so). Or is that not true any longer? Philipp * Of course, the true definition of DNS might be a bit unclear; we typically say that a DNS resolves all relevant scales of motion, but what are these, really? On 2018-02-09 21:12, [email protected] wrote:
The turbChannel example is using a high pass filter relaxation term as SGS. For a DNS just
- set lx1=8 and lxd=12 in SIZE - generate a finer mesh with more elements using genbox (if you change the mesh make sure to delete the old amg files) - set filtering=no in par
-----Original message-----
From:[email protected] <[email protected]> Sent: Friday 9th February 2018 20:32 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
Hello Paul, Thank you a lot for your explanation; it really helps. For now, I am using the most recent turChannel example of NEK5000 V.17. I successfully simulated a turbulent channel with a Retau of 180 using 1536 elements (I am aware of its a lot of elements). The default settings were applied. I wonder is it in the .par file where you do the modification to convert it into DNS? Or somewhere else as well? Again, thank you for the help, Emily _______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
Yes it will turn it off. I agree this depends on the resolution. If you are really well resolved dealising is typicaly enough to make it stable otherwise you have to add filtering. -----Original message-----
From:[email protected] <[email protected]> Sent: Saturday 10th February 2018 10:52 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
does "filtering=no" turn off the filtering completely? As far as I understand, even for DNS* some low amounts of filtering is needed (1% or so). Or is that not true any longer?
Philipp
* Of course, the true definition of DNS might be a bit unclear; we typically say that a DNS resolves all relevant scales of motion, but what are these, really?
On 2018-02-09 21:12, [email protected] wrote:
The turbChannel example is using a high pass filter relaxation term as SGS. For a DNS just
- set lx1=8 and lxd=12 in SIZE - generate a finer mesh with more elements using genbox (if you change the mesh make sure to delete the old amg files) - set filtering=no in par
-----Original message-----
From:[email protected] <[email protected]> Sent: Friday 9th February 2018 20:32 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
Hello Paul, Thank you a lot for your explanation; it really helps. For now, I am using the most recent turChannel example of NEK5000 V.17. I successfully simulated a turbulent channel with a Retau of 180 using 1536 elements (I am aware of its a lot of elements). The default settings were applied. I wonder is it in the .par file where you do the modification to convert it into DNS? Or somewhere else as well? Again, thank you for the help, Emily _______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
_______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
We typically have filtering on with low amplitude even for DNS (say 1%); in particular at high Re (whatever that means...). Dealiasing is always on for us. Philipp On 2018-02-10 11:54, [email protected] wrote:
Yes it will turn it off. I agree this depends on the resolution. If you are really well resolved dealising is typicaly enough to make it stable otherwise you have to add filtering.
-----Original message-----
From:[email protected] <[email protected]> Sent: Saturday 10th February 2018 10:52 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
does "filtering=no" turn off the filtering completely? As far as I understand, even for DNS* some low amounts of filtering is needed (1% or so). Or is that not true any longer?
Philipp
* Of course, the true definition of DNS might be a bit unclear; we typically say that a DNS resolves all relevant scales of motion, but what are these, really?
On 2018-02-09 21:12, [email protected] wrote:
The turbChannel example is using a high pass filter relaxation term as SGS. For a DNS just
- set lx1=8 and lxd=12 in SIZE - generate a finer mesh with more elements using genbox (if you change the mesh make sure to delete the old amg files) - set filtering=no in par
-----Original message-----
From:[email protected] <[email protected]> Sent: Friday 9th February 2018 20:32 To: [email protected] Subject: Re: [Nek5000-users] DNS of turbChannel
Hello Paul, Thank you a lot for your explanation; it really helps. For now, I am using the most recent turChannel example of NEK5000 V.17. I successfully simulated a turbulent channel with a Retau of 180 using 1536 elements (I am aware of its a lot of elements). The default settings were applied. I wonder is it in the .par file where you do the modification to convert it into DNS? Or somewhere else as well? Again, thank you for the help, Emily _______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
_______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
_______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
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