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

Discrete adjoint returns almost zero sensitivities with inverse design objective

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 12, 2018, 15:35
Post Discrete adjoint returns almost zero sensitivities with inverse design objective
  #1
Zen
Member
 
Zeno
Join Date: Sep 2013
Location: Delft, The Netherlands
Posts: 62
Rep Power: 9
Zen is on a distinguished road
Hello,

I downloaded the test case 'steady_inverse_adjoint' from the GitHub page of SU2 and I tried to run a shape optimization with a discrete adjoint method.

The optimization terminates after one single function and adjoint evaluation since the sensitivities are O(1e-11).

On the other hand, when running the optimization with a continuous adjoint technique, everything works fine and a minimum is reached after 28 function and 11 gradient evaluations.

Any idea why this happens?

Thank for the help,

Z
Zen is offline   Reply With Quote

Old   March 17, 2018, 07:28
Default
  #2
Super Moderator
 
Tim Albring
Join Date: Sep 2015
Posts: 195
Rep Power: 7
talbring is on a distinguished road
Hi Zen,

the answer is simple: this objective function cannot be used for the discrete adjoint at the moment. It is not a big deal to implement it ...actually is very simple. Do you want to give it a try ? Let me know, I can point you to the correct places.

Tim
__________________
Developer Director @ SU2 Foundation

Get involved:
talbring is offline   Reply With Quote

Old   March 17, 2018, 10:10
Default
  #3
Zen
Member
 
Zeno
Join Date: Sep 2013
Location: Delft, The Netherlands
Posts: 62
Rep Power: 9
Zen is on a distinguished road
Hi Tim,

I solved the problem by inserting the following lines after DirectRun(); in CDiscAdjFluidDriver::SetRecording(unsigned short kind_recording):

Code:
 if (config_container[ZONE_0]->GetInvDesign_Cp() == YES){
output->SetCp_InverseDesign(solver_container[ZONE_0][MESH_0][FLOW_SOL],
geometry_container[ZONE_0][MESH_0], config_container[ZONE_0], ExtIter);
}
This actually solves a small bug concerning the evaluation of Total_CpDiff and makes the optimization work correctly.



Z



P.S. Probably, this should also be done for INVERSE_DESIGN_HEATFLUX.
Zen is offline   Reply With Quote

Old   March 18, 2018, 21:43
Default
  #4
Super Moderator
 
Francisco Palacios
Join Date: Jan 2013
Location: Long Beach, CA
Posts: 404
Rep Power: 11
fpalacios is on a distinguished road
Hi Zen,

Glad you are working on this. As you know, Cp inverse design is a very useful capability in aero design. It seems that you are also familiar with the software as developer, if you have a while the SU2 community would appreciate if you could add the changes in GitHub.

By the way, we are creating the SU2 International Developers Society, it maybe be interesting for you (www.su2devsociety.org).

Best,
Francisco
fpalacios is offline   Reply With Quote

Reply

Tags
discrete adjoints, inverse design, shape optimization

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Discrete vs Continuous Adjoint solution variable: Scaling/normalization issue? asitav SU2 2 November 21, 2018 20:11
Shape optimization doesn't converge - Adjoint log file JPBLourenco SU2 Shape Design 0 December 11, 2017 09:41
Difficulties running 3D inverse design optimisations dominico SU2 Shape Design 1 September 19, 2017 09:56
Is SU2 able to handle adjoint for pressure distribution when doing inverse design? Xiaosong SU2 2 December 4, 2016 01:25
Info: Short Course On Thermal Design of Electronic Equipment Arnold Free Main CFD Forum 0 August 10, 1999 11:18


All times are GMT -4. The time now is 14:26.