******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear All, How may I calculate the time-average of a gradient, for example velocity gradient? Kind regards syavash
Hi Syavash, You could use FieldConvert -m gradient on the time-averaged fields. Regards, Chi Hin Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Ehsan Asgari <eh.asgari@gmail.com> Sent: Saturday, June 17, 2023 8:20:29 PM To: nektar-users <nektar-users@imperial.ac.uk> Subject: [Nektar-users] Time-average of a gradient This email from eh.asgari@gmail.com originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Dear All, How may I calculate the time-average of a gradient, for example velocity gradient? Kind regards syavash
Hi Chi Hin Thanks. You are right about the velocity gradient alone. Sorry, I didn't ask the right question. What can be done when we have a product of velocity gradients? More precisely, I need to calculate the TKE viscous dissipation term: nu*<s_ij s_ij>, where s_ij refers to the fluctuation strain rate tensor. I need this quantity to subsecuently calculate the Kolmogorov length scale. I see it calculated in a paper that has utilized Nektar++, but I have not a clear idea how it was done. Kind regards syavash On Sun, Jun 18, 2023, 14:03 Chan, Chi Hin <chi.chan19@imperial.ac.uk> wrote:
Hi Syavash,
You could use FieldConvert -m gradient on the time-averaged fields.
Regards, Chi Hin
Get Outlook for iOS <https://aka.ms/o0ukef> ------------------------------ *From:* nektar-users-bounces@imperial.ac.uk < nektar-users-bounces@imperial.ac.uk> on behalf of Ehsan Asgari < eh.asgari@gmail.com> *Sent:* Saturday, June 17, 2023 8:20:29 PM *To:* nektar-users <nektar-users@imperial.ac.uk> *Subject:* [Nektar-users] Time-average of a gradient
This email from eh.asgari@gmail.com originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list <https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address.
Dear All,
How may I calculate the time-average of a gradient, for example velocity gradient?
Kind regards syavash
Hi Syavash, I'm not exactly familiar with computing viscous dissipation but I think that it could be computed with the enstrophy with the "energy" filter. There's a tutorial on Taylor Green's vortex on this, https://doc.nektar.info/tutorials/latest/incns/taylor-green-vortex/incns-tay... Hope this helps. Cheers, Chi Hin ________________________________ From: Ehsan Asgari <eh.asgari@gmail.com> Sent: 18 June 2023 11:56 To: Chan, Chi Hin <chi.chan19@imperial.ac.uk> Cc: nektar-users <nektar-users@imperial.ac.uk> Subject: Re: [Nektar-users] Time-average of a gradient Hi Chi Hin Thanks. You are right about the velocity gradient alone. Sorry, I didn't ask the right question. What can be done when we have a product of velocity gradients? More precisely, I need to calculate the TKE viscous dissipation term: nu*<s_ij s_ij>, where s_ij refers to the fluctuation strain rate tensor. I need this quantity to subsecuently calculate the Kolmogorov length scale. I see it calculated in a paper that has utilized Nektar++, but I have not a clear idea how it was done. Kind regards syavash On Sun, Jun 18, 2023, 14:03 Chan, Chi Hin <chi.chan19@imperial.ac.uk<mailto:chi.chan19@imperial.ac.uk>> wrote: Hi Syavash, You could use FieldConvert -m gradient on the time-averaged fields. Regards, Chi Hin Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ From: nektar-users-bounces@imperial.ac.uk<mailto:nektar-users-bounces@imperial.ac.uk> <nektar-users-bounces@imperial.ac.uk<mailto:nektar-users-bounces@imperial.ac.uk>> on behalf of Ehsan Asgari <eh.asgari@gmail.com<mailto:eh.asgari@gmail.com>> Sent: Saturday, June 17, 2023 8:20:29 PM To: nektar-users <nektar-users@imperial.ac.uk<mailto:nektar-users@imperial.ac.uk>> Subject: [Nektar-users] Time-average of a gradient This email from eh.asgari@gmail.com<mailto:eh.asgari@gmail.com> originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Dear All, How may I calculate the time-average of a gradient, for example velocity gradient? Kind regards syavash
participants (2)
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Chan, Chi Hin
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Ehsan Asgari