Dear David, Thanks a lot for making the changes. I will do regress test of RBC stability, and update you soon. With regards Abhishek On Wed, Feb 7, 2018 at 6:07 PM, David Moxey <D.Moxey@exeter.ac.uk> wrote:
Hi Abhishek,
Okay, that issue was pretty straightforward to solve -- advection was not being calculated for the scalar field. I have pushed that fix up to the repository, and I now get a positive eigenvalue of 2.1124 with your XML file, so pretty close to your reference value.
Thanks,
Dave
On 7 Feb 2018, at 15:24, Abhishek Kumar <abhishek.kir@gmail.com> wrote:
Dear David,
Thanks for your response.
I have attached the XML file for RBC stability. I am running for Ra=2000 with k=3.117. The critical value of Rayleigh number for this configuration is 1708.
The growth rate for Ra=2000 of the most unstable mode should be 2.1464. However, I am getting -9.8699, a negative growth rate, which is not possible as Ra > Ra critical.
With regards Abhishek
On Wed, Feb 7, 2018 at 2:50 PM, David Moxey <D.Moxey@exeter.ac.uk> wrote: Hi Abhishek,
Thanks for the update, glad to hear we are producing correct results on that front.
Regarding the linear stability; can you share your XML file? It might just be that the base flow needs to be properly imposed in the appropriate scalar -- we probably haven't taken scalar fields into account yet in the setup.
Thanks,
Dave
On 6 Feb 2018, at 13:20, Abhishek Kumar <abhishek.kir@gmail.com> wrote:
Dear David,
Thanks for your answer. Now, I got it.
You would be happy to know that the Rayleigh-Benard convection (RBC) solver is working properly with Nektar++. I have tested the solver and also did a benchmark with Clever & Busse JFM 1974 for the Nusselt number calculation. There is an excellent agreement.
Now, I am trying to do the direct linear stability for RBC. But, I find there is a problem with the base flow addition for the buoyant scalar. I have reported this issue on the forum. Could you kindly also check this issue.
Again, thanks for your response.
With regards Abhishek
On Mon, Feb 5, 2018 at 5:15 PM, David Moxey <D.Moxey@exeter.ac.uk> wrote: Hi Abhishek,
These define the various choice of basis functions; the first is the modified C^0 basis that's defined in Karniadakis & Sherwin. The other two are Lagrange basis functions: the first is a choice with the number of quadrature points as one higher than the number of points; the other is where they are equal (i.e. the collocated basis with diagonal mass matrix).
I believe all of those basis functions should work fine for 2D elements. For 3D, Lagrange only presently works for hex elements, whereas the C^0 has full support for hex/tet/prism/pyramid.
Hope that helps,
Dave
On 1 Feb 2018, at 17:42, Abhishek Kumar <abhishek.kir@gmail.com> wrote:
Dear friends,
I am new to NEKTAR++.
Can someone tell me the difference between MODIFIED, GLL_LAGRANGE, GLL_LAGRANGE_SEM expansions type?
With regards Abhishek Kumar
------------------------------------------------------------
Abhishek Kumar Post Doctoral Researcher Applied Mathematics Research Centre Coventry University, Coventry CV15FB The United Kingdom
Email # ac7600@coventry.ac.uk, abhishek.kir@gmail.com ------------------------------------------------------------
_______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
-- With regards Abhishek Kumar
------------------------------------------------------------
Abhishek Kumar Post Doctoral Researcher Applied Mathematics Research Centre Coventry University, Coventry CV15FB The United Kingdom
Email # ac7600@coventry.ac.uk, abhishek.kir@gmail.com ------------------------------------------------------------
_______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
-- With regards Abhishek Kumar
------------------------------------------------------------
Abhishek Kumar Post Doctoral Researcher Applied Mathematics Research Centre Coventry University, Coventry CV15FB The United Kingdom
Email # ac7600@coventry.ac.uk, abhishek.kir@gmail.com ------------------------------------------------------------
<rbc_stability.xml>_______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
-- With regards Abhishek Kumar --------------------------------------------------------------------------------------- Abhishek Kumar Post Doctoral Researcher Applied Mathematics Research Centre Coventry University, Coventry CV15FB The United Kingdom Email # ac7600@coventry.ac.uk, abhishek.kir@gmail.com ---------------------------------------------------------------------------------------