CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > SU2

Discrete vs Continuous Adjoint solution variable: Scaling/normalization issue?

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 25, 2016, 15:57
Default Discrete vs Continuous Adjoint solution variable: Scaling/normalization issue?
  #1
New Member
 
Asitav Mishra
Join Date: Oct 2016
Posts: 1
Rep Power: 0
asitav is on a distinguished road
Hello all,

Why are the Discrete adjoint solution (psiRho, for ex) values order of magnitude different from the Continuous adjoint solution values? Referring to the QuickStart tutorial, I could match exactly with the continuous adjoint solution. However, when run with MATH_PROBLEM=DISCRETE_ADJOINT option with the same config file (inv_NACA0012.cfg) the adjoint solution variables is order of magnitude different than the continuous adjoint. See attached figures. The figures also include Continuous vs Discrete surface sensitivity plot.

I actually verified the Discrete adjoint sensitivity with the Direct Derivatives, besides verifying dCd/dM from FD with Disc Adj. Is there some internal normalization for Disc Adjoint solution that is saved in adjoint restart file?
Any pointers would help.
Attached Images
File Type: png discVsDirDiff.png (8.2 KB, 63 views)
File Type: png surfSensCmp.png (8.9 KB, 63 views)
File Type: png adjCont.png (13.2 KB, 64 views)
File Type: png adjDisc.png (38.2 KB, 62 views)
asitav is offline   Reply With Quote

Old   March 19, 2018, 10:12
Default
  #2
Zen
Member
 
Zeno
Join Date: Sep 2013
Location: Delft, The Netherlands
Posts: 63
Rep Power: 13
Zen is on a distinguished road
This is something I am also experiencing. Did you find the reason for this in the end?

Z
Zen is offline   Reply With Quote

Old   November 21, 2018, 20:11
Default
  #3
New Member
 
Robert_87
Join Date: Nov 2018
Posts: 1
Rep Power: 0
Robert_87 is on a distinguished road
I guess you used two different configuration files for continuous and discrete runs.

You might look at the REF_DIMENSIONALIZATION in the configuration file and make sure that the non-dimensionalization is the same between the two adjoint runs.
Robert_87 is offline   Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
2way FSi, Initialize with steady solution, Fluent, Transient Sturcural, System Coupli mmkkeshavarzi FLUENT 1 June 28, 2024 08:03
Fluent Adjoint Solver Convergence Issue? ex10148 FLUENT 2 July 25, 2016 15:41
Status of continuous RANS adjoint praveen SU2 1 April 11, 2013 14:12
Discrete Adjoint Optimization ? Tommy Chen SU2 Shape Design 1 March 5, 2013 15:08
Question about Continuous Adjoint Method fumiya Main CFD Forum 6 November 1, 2011 11:09


All times are GMT -4. The time now is 15:07.