Question about vector correction function in PyFR.

20 views
Skip to first unread message

Kiny Wan

unread,
Jul 18, 2020, 3:28:25 AM7/18/20
to PyFR Mailing List
Hello everyone,
        I recently read the book about high-order flux reconstruction schemes and found the vector correction function for triangle element. I would like to ask a question about how to get these vectors in PyFR? The references include the Ph.D. thesis of P. Castonguay and the chapter 10 of F.D. Witherden, P.E. Vincent and A. Jameson.

Regards
Kiny


correction function.jpg

Freddie Witherden

unread,
Jul 18, 2020, 9:32:26 AM7/18/20
to Kiny Wan, PyFR Mailing List
Hi,

During an FR step one only needs the divergence of these functions.  Moreover, it turns out to be simpler to directly compute the divergence of these functions.  This is the approach taken by PyFR.

Regards, Freddie.

On 18 Jul 2020, at 02:28, Kiny Wan <wlc...@gmail.com> wrote:

Hello everyone,
        I recently read the book about high-order flux reconstruction schemes and found the vector correction function for triangle element. I would like to ask a question about how to get these vectors in PyFR? The references include the Ph.D. thesis of P. Castonguay and the chapter 10 of F.D. Witherden, P.E. Vincent and A. Jameson.

Regards
Kiny


<correction function.jpg>

--
You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pyfrmailingli...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/pyfrmailinglist/ef2434b3-1fe1-43ff-bd5b-cea3ae0ee240n%40googlegroups.com.
<correction function.jpg>

Vincent, Peter E

unread,
Jul 18, 2020, 4:08:19 PM7/18/20
to Kiny Wan, PyFR Mailing List
Hi Kiny,

As Freddie says, PyFR only deals with the divergence of these correction functions, and not the vector correction functions themselves.

The DG variants are the default coded into PyFR.

To try others you could adopt an approach similar to that which Brian adopted here for tensor product elements:


in which I believe he modified the code for calculating the m3 matrix to read from a file instead of calling gbasis_at (there should be a patch in the Supplementary Material).

One warning about this approach, is that the m3 coefficients you read from a file will have to have been generated in the context of a specific set of solution points, so if you run with anything but those solutions points it will lead to problems! I guess another approach would be to generalise gbasis_at.

Thanks

Peter 

Dr Peter Vincent MSci ARCS DIC PhD FRAeS
Reader in Aeronautics and EPSRC Fellow
Department of Aeronautics
Imperial College London
South Kensington
London
SW7 2AZ
UK



Kiny Wan

unread,
Jul 20, 2020, 12:08:59 AM7/20/20
to PyFR Mailing List
Thank you Freddie. I finally understand what you mean. It is more convenient to use the divergence of correction function as they are fixed form. Regards Kiny

Kiny Wan

unread,
Jul 20, 2020, 12:35:44 AM7/20/20
to PyFR Mailing List
Reply all
Reply to author
Forward
0 new messages