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-   -   Problems with the values of "OBJFUNC_SCALE" (https://www.cfd-online.com/Forums/su2/115335-problems-values-objfunc_scale.html)

Fang-SIAMM March 28, 2013 10:16

Problems with the values of "OBJFUNC_SCALE"
 
Hi, everyone.
I'm using the SU2 to optimize NACA0012 airfoil, but i don't know how to set the values of "OBJFUNC_SCALE" when I choose 'NEARFIELD-PRESSURE' as the OBJFUNC.
Is there anyone can help me?
Thinks in advance.

aniketaranake April 11, 2013 13:27

Quote:

Originally Posted by Fang-SIAMM (Post 417018)
Hi, everyone.
I'm using the SU2 to optimize NACA0012 airfoil, but i don't know how to set the values of "OBJFUNC_SCALE" when I choose 'NEARFIELD-PRESSURE' as the OBJFUNC.
Is there anyone can help me?
Thinks in advance.

Hello Fang-SIAMM,

The purpose of OBJFUNC_SCALE is to ensure that the initial step of a design iteration is reasonable. Without it, the optimizer may take an excessively large step at the first iteration, which often results in unfeasible and undesired geometries. The appropriate way to set it is with a little bit of guess-and-test. A typical value for a 2D airfoil optimization with chord length 1.0 using Hicks-Henne bump functions is between 1e-3 and 1e-4.

Regards,
Aniket


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