Dear all, I think there is a major bug in aero-forces filter for 3D1H case. It does not take into account the length in homogenous direction, LZ, while evaluating integrals. So LZ seems to be always 1. So basically, all the calculated forces are wrong for 3D1H problems. My LZ is close to unity so I almost didn't notice it. I was wondering if it is just calculating force on one slice or do some hidden normalization in third direction. Best. Asim
Hi Asim, Yes, the forces are per unit length. I think this is a reasonable convention, considering in 3DH1D we have an infinite periodic domain. Cheers, Douglas ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Asım Önder <asim.onder@gmail.com> Sent: 06 November 2016 12:42:56 To: nektar-users Subject: [Nektar-users] bug in aero-forces filter Dear all, I think there is a major bug in aero-forces filter for 3D1H case. It does not take into account the length in homogenous direction, LZ, while evaluating integrals. So LZ seems to be always 1. So basically, all the calculated forces are wrong for 3D1H problems. My LZ is close to unity so I almost didn't notice it. I was wondering if it is just calculating force on one slice or do some hidden normalization in third direction. Best. Asim
Hi Douglas, Indeed, it makes perfectly sense and it is pretty handy like this. Sorry for claiming it as a bug. Still, it would be nice to have a comment on this somewhere to remind the user. I have one more periodic direction with p-expansions where normalization is apparently not applied. It is a bit tricky like this. Thanks, Asim On Sun, Nov 6, 2016 at 11:39 PM, Serson, Douglas <d.serson14@imperial.ac.uk> wrote:
Hi Asim,
Yes, the forces are per unit length.
I think this is a reasonable convention, considering in 3DH1D we have an infinite periodic domain.
Cheers,
Douglas ------------------------------ *From:* nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@ imperial.ac.uk> on behalf of Asım Önder <asim.onder@gmail.com> *Sent:* 06 November 2016 12:42:56 *To:* nektar-users *Subject:* [Nektar-users] bug in aero-forces filter
Dear all,
I think there is a major bug in aero-forces filter for 3D1H case. It does not take into account the length in homogenous direction, LZ, while evaluating integrals. So LZ seems to be always 1.
So basically, all the calculated forces are wrong for 3D1H problems. My LZ is close to unity so I almost didn't notice it.
I was wondering if it is just calculating force on one slice or do some hidden normalization in third direction.
Best. Asim
-- Asim
HI Asim, Douglas, Could we post a ticket for this time on the nektar page and we can then look to include this in the documentation and/or file output. Cheers, Spencer. On 6 Nov 2016, at 16:09, Asım Önder <asim.onder@gmail.com<mailto:asim.onder@gmail.com>> wrote: Hi Douglas, Indeed, it makes perfectly sense and it is pretty handy like this. Sorry for claiming it as a bug. Still, it would be nice to have a comment on this somewhere to remind the user. I have one more periodic direction with p-expansions where normalization is apparently not applied. It is a bit tricky like this. Thanks, Asim On Sun, Nov 6, 2016 at 11:39 PM, Serson, Douglas <d.serson14@imperial.ac.uk<mailto:d.serson14@imperial.ac.uk>> wrote: Hi Asim, Yes, the forces are per unit length. I think this is a reasonable convention, considering in 3DH1D we have an infinite periodic domain. Cheers, Douglas ________________________________ 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 Asım Önder <asim.onder@gmail.com<mailto:asim.onder@gmail.com>> Sent: 06 November 2016 12:42:56 To: nektar-users Subject: [Nektar-users] bug in aero-forces filter Dear all, I think there is a major bug in aero-forces filter for 3D1H case. It does not take into account the length in homogenous direction, LZ, while evaluating integrals. So LZ seems to be always 1. So basically, all the calculated forces are wrong for 3D1H problems. My LZ is close to unity so I almost didn't notice it. I was wondering if it is just calculating force on one slice or do some hidden normalization in third direction. Best. Asim -- Asim _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052
participants (3)
-
Asım Önder
-
Serson, Douglas
-
Sherwin, Spencer J