CFD Online Discussion Forums - Adjoint Calculation Error

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- SU2 Shape Design (https://www.cfd-online.com/Forums/su2-shape-design/)

- - Adjoint Calculation Error (https://www.cfd-online.com/Forums/su2-shape-design/191895-adjoint-calculation-error.html)

Adjoint Calculation Error

Hi,
I am running a 2D aerofoil optimization using V5.0.0;
the flow solution is converged but each log_adjoint.out file shows the following:

Code:

log10[Maximum residual]: -inf.

Maximum residual point 0, located at (0, 0).



 Iter    Time(s)   Res[Psi_Rho]     Res[Psi_E]      Sens_Geo      Sens_AoA

    0   0.524635     -32.000000     -32.000000    0.0000e+00    0.0000e+00

CSysSolve::FGMRES(): system solved by initial guess.

when in fact the flow solution file shows the following:

Code:

----------------------- Residual Evolution Summary ----------------------

log10[Maximum residual]: -2.83626.

Maximum residual point 11866, located at (0.191485, -0.0191805).

----------------------------------------------------------------------

just before writing and exiting.
the adjoint gradients are then calculated to be zero (i think as a result of the above issue)
any help would be highly appreciated!
if more information on the .cfg file or .su2 grid is needed let me know.
Many thanks!
Tom

What are the values you are using in the reduction factors of the CFL? This issue can happen if they are 0 since you'll be using a CFL of 0.

Hi,
the CFL was positive with a value of around 0.5-1.5.
the reduction factors were around 1.0-0.9.
I have now gotten around the problem by modifying a cfg file from the NACA0012 steady optimization Testcase for use with my own grid and conditions.
However, i am now facing the problem of the design returning to its original condition after a single 'good' design iteration. This issue is being discussed in another Thread.
Thanks for the assistance.
Tom