Solve scalar transport equation along with Incompressible Navier Stokes
Hello all, I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into? I greatly appreciate any help regarding this problem Thank you, Siddarth
Dear Siddarth, Sorry for a flow response. In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future. If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow. It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields. Cheers, Spencer. On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com<mailto:siddarth.ch1990@gmail.com>> wrote: Hello all, I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into? I greatly appreciate any help regarding this problem Thank you, Siddarth _______________________________________________ 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
Hi Spencer, After fixing a couple of things I think I was able to run this using the incompressible solver (I pushed the changes to the branch fix/IncNSExtraFields). In my branch doing this is just a matter of defining the scalar fields after the velocity (p needs to be the last variable) with appropriate boundary conditions and set the (constant) coefficients using the function "DiffusionCoefficient". This way we can have multiple scalar fields with different coefficients. Cheers, Douglas ________________________________ From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Sherwin, Spencer J <s.sherwin@imperial.ac.uk> Sent: 02 May 2016 09:49:02 To: Siddarth Chintamani Cc: nektar-users Subject: Re: [Nektar-users] Solve scalar transport equation along with Incompressible Navier Stokes Dear Siddarth, Sorry for a flow response. In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future. If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow. It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields. Cheers, Spencer. On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com<mailto:siddarth.ch1990@gmail.com>> wrote: Hello all, I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into? I greatly appreciate any help regarding this problem Thank you, Siddarth _______________________________________________ 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
Hi Siddarth, Can you give Douglas’ branch a go to see if it meets your requirements. Cheers, Spencer. On 2 May 2016, at 22:26, Serson, Douglas <d.serson14@imperial.ac.uk<mailto:d.serson14@imperial.ac.uk>> wrote: Hi Spencer, After fixing a couple of things I think I was able to run this using the incompressible solver (I pushed the changes to the branch fix/IncNSExtraFields). In my branch doing this is just a matter of defining the scalar fields after the velocity (p needs to be the last variable) with appropriate boundary conditions and set the (constant) coefficients using the function "DiffusionCoefficient". This way we can have multiple scalar fields with different coefficients. 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 Sherwin, Spencer J <s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk>> Sent: 02 May 2016 09:49:02 To: Siddarth Chintamani Cc: nektar-users Subject: Re: [Nektar-users] Solve scalar transport equation along with Incompressible Navier Stokes Dear Siddarth, Sorry for a flow response. In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future. If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow. It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields. Cheers, Spencer. On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com<mailto:siddarth.ch1990@gmail.com>> wrote: Hello all, I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into? I greatly appreciate any help regarding this problem Thank you, Siddarth _______________________________________________ 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 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
Dear Douglas and Spencer, I ran the solver with the changes and it's working. You saved me a lot of time. I really appreciate your help. Thank you very much, Siddarth On 2 May 2016 at 16:56, Sherwin, Spencer J <s.sherwin@imperial.ac.uk> wrote:
Hi Siddarth,
Can you give Douglas’ branch a go to see if it meets your requirements.
Cheers, Spencer.
On 2 May 2016, at 22:26, Serson, Douglas <d.serson14@imperial.ac.uk> wrote:
Hi Spencer,
After fixing a couple of things I think I was able to run this using the incompressible solver (I pushed the changes to the branch fix/IncNSExtraFields). In my branch doing this is just a matter of defining the scalar fields after the velocity (p needs to be the last variable) with appropriate boundary conditions and set the (constant) coefficients using the function "DiffusionCoefficient". This way we can have multiple scalar fields with different coefficients.
Cheers, Douglas ------------------------------ *From:* nektar-users-bounces@imperial.ac.uk < nektar-users-bounces@imperial.ac.uk> on behalf of Sherwin, Spencer J < s.sherwin@imperial.ac.uk> *Sent:* 02 May 2016 09:49:02 *To:* Siddarth Chintamani *Cc:* nektar-users *Subject:* Re: [Nektar-users] Solve scalar transport equation along with Incompressible Navier Stokes
Dear Siddarth,
Sorry for a flow response.
In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future.
If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow.
It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields.
Cheers, Spencer.
On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com> wrote:
Hello all,
I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into?
I greatly appreciate any help regarding this problem
Thank you, Siddarth _______________________________________________ Nektar-users mailing list 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 +44 (0) 20 759 45052
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 +44 (0) 20 759 45052
Hi Siddarth, Hi Siddarth, It would be helpful for us if you can suggest some modifications to the user manual to update for these changes so we can add them when we merge this branch. Just some plain text would be a help to give us some material for inclusion. Cheers, Spencer. On 3 May 2016, at 00:12, Siddarth Chintamani <siddarth.ch1990@gmail.com<mailto:siddarth.ch1990@gmail.com>> wrote: Dear Douglas and Spencer, I ran the solver with the changes and it's working. You saved me a lot of time. I really appreciate your help. Thank you very much, Siddarth On 2 May 2016 at 16:56, Sherwin, Spencer J <s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk>> wrote: Hi Siddarth, Can you give Douglas’ branch a go to see if it meets your requirements. Cheers, Spencer. On 2 May 2016, at 22:26, Serson, Douglas <d.serson14@imperial.ac.uk<mailto:d.serson14@imperial.ac.uk>> wrote: Hi Spencer, After fixing a couple of things I think I was able to run this using the incompressible solver (I pushed the changes to the branch fix/IncNSExtraFields). In my branch doing this is just a matter of defining the scalar fields after the velocity (p needs to be the last variable) with appropriate boundary conditions and set the (constant) coefficients using the function "DiffusionCoefficient". This way we can have multiple scalar fields with different coefficients. 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 Sherwin, Spencer J <s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk>> Sent: 02 May 2016 09:49:02 To: Siddarth Chintamani Cc: nektar-users Subject: Re: [Nektar-users] Solve scalar transport equation along with Incompressible Navier Stokes Dear Siddarth, Sorry for a flow response. In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future. If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow. It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields. Cheers, Spencer. On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com<mailto:siddarth.ch1990@gmail.com>> wrote: Hello all, I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into? I greatly appreciate any help regarding this problem Thank you, Siddarth _______________________________________________ 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 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 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
Hi Spencer, I have attached the file with material that could be included in user guide. On a side note, it is also possible to activate/specify different SVV coefficients for the Navier stokes and the transport equations solved for extra fields by making slight changes in the file VelocityCorrectionScheme.cpp. This feature might be helpful if the diffusion coefficient is too small. In such a case, the mesh spacing required to resolve all physical scales associated with the transport equation (the smallest scale is Batchelor scale) becomes too small (smaller than Kolmogorov scale). So it makes sense to activate SVV only for the transport equation if we resolve upto Kolmogorov scale (this is kind of like DNS solution for velocity and Implicit LES solution for the extra field).
From my simulations, I observed that small diffusion coefficient leads to spurious oscillations in extra field solution. One way to avoid these oscillations is to activate SVV for the transport equation.
Thanks and regards, Siddarth On 3 May 2016 at 11:48, Sherwin, Spencer J <s.sherwin@imperial.ac.uk> wrote:
Hi Siddarth,
Hi Siddarth,
It would be helpful for us if you can suggest some modifications to the user manual to update for these changes so we can add them when we merge this branch. Just some plain text would be a help to give us some material for inclusion.
Cheers, Spencer.
On 3 May 2016, at 00:12, Siddarth Chintamani <siddarth.ch1990@gmail.com> wrote:
Dear Douglas and Spencer,
I ran the solver with the changes and it's working. You saved me a lot of time.
I really appreciate your help.
Thank you very much, Siddarth
On 2 May 2016 at 16:56, Sherwin, Spencer J <s.sherwin@imperial.ac.uk> wrote:
Hi Siddarth,
Can you give Douglas’ branch a go to see if it meets your requirements.
Cheers, Spencer.
On 2 May 2016, at 22:26, Serson, Douglas <d.serson14@imperial.ac.uk> wrote:
Hi Spencer,
After fixing a couple of things I think I was able to run this using the incompressible solver (I pushed the changes to the branch fix/IncNSExtraFields). In my branch doing this is just a matter of defining the scalar fields after the velocity (p needs to be the last variable) with appropriate boundary conditions and set the (constant) coefficients using the function "DiffusionCoefficient". This way we can have multiple scalar fields with different coefficients.
Cheers, Douglas ------------------------------ *From:* nektar-users-bounces@imperial.ac.uk < nektar-users-bounces@imperial.ac.uk> on behalf of Sherwin, Spencer J < s.sherwin@imperial.ac.uk> *Sent:* 02 May 2016 09:49:02 *To:* Siddarth Chintamani *Cc:* nektar-users *Subject:* Re: [Nektar-users] Solve scalar transport equation along with Incompressible Navier Stokes
Dear Siddarth,
Sorry for a flow response.
In principle it should be possible to set up more advection fields in the incompressible Navier-Stokes solver. Which could then be used as advection fields. However I am not sure this has yet been attempted by anyone. Also I fear that the ability to specify a different parameter for the advection field has been allows so I imagine this will not work at present but may well have been an easier approach in the future.
If you have a steady base flow then calling the advection-diffusion solver may well work. Although from your email it should like you might be attempting to call the advection-diffusion solver from a script? This could be very slow.
It might be interesting to see if more advection fields can be set up in the incompressible Navier-Stokes from the .xml file and first see what happens. If we can get this running we could then see what the best way of specifying the diffusion coefficient might for advected fields.
Cheers, Spencer.
On 20 Apr 2016, at 10:30, Siddarth Chintamani <siddarth.ch1990@gmail.com> wrote:
Hello all,
I am trying to study scalar mixing from a jet. I can use the incompressible Navier Stokes solver to get the velocity at every time step. I am thinking of calling the advection-diffusion solver from the Navier Stokes solver every time step and solve for the scalar mixing. I was wondering if there is any other easier approach? Is there any example that I can look into?
I greatly appreciate any help regarding this problem
Thank you, Siddarth _______________________________________________ Nektar-users mailing list 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 +44 (0) 20 759 45052
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 +44 (0) 20 759 45052
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 +44 (0) 20 759 45052
participants (3)
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Serson, Douglas
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Sherwin, Spencer J
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Siddarth Chintamani