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-   -   Parameters selection option for shape optimization (https://www.cfd-online.com/Forums/su2-shape-design/129524-parameters-selection-option-shape-optimization.html)

shsreekanth February 7, 2014 02:29

Parameters selection option for shape optimization
 
Hi,

I see that SU2 has many options for parameter selection, like 1-Hicks_henne ,2 -cosine_bump ...5-Displacement etc..
In the config_template it gives the syntax of each option. But I would like to know what each option does. The SU2 paper talks about Hicks-henne and FFD but nothing about other options. I am interested specially in the displacement option. Can you tell me how it works? Also could you point me to any documentation material regarding this?

Sreekanth

shsreekanth February 10, 2014 12:32

Parameters selection option for shape optimization
 
Hi,

1) I see that SU2 has many options for parameter selection, like 1-Hicks_henne ,2 -cosine_bump ...5-Displacement etc..
In the config_template it gives the syntax of each option. But I would like to know what each option does. The SU2 paper talks about Hicks-henne and FFD but nothing about other options.
2) What does DV_PARAM and DV_VALUE options do? How do you set it for cases other than FFD and HICKS_HENNE?
I am interested specially in the displacement option. Can you tell me how it works? Also could you point me to any documentation material regarding this?

Sreekanth

economon February 12, 2014 22:07

Hi Sreekanth,

Quote:

Originally Posted by shsreekanth (Post 474305)

1) I see that SU2 has many options for parameter selection, like 1-Hicks_henne ,2 -cosine_bump ...5-Displacement etc..
In the config_template it gives the syntax of each option. But I would like to know what each option does. The SU2 paper talks about Hicks-henne and FFD but nothing about other options.

At the moment, we do not have further written documentation on all of the available design variables (we're working on this). For now, please see the subroutines that control these variables, as most are short/simple routines for moving airfoil surfaces and will be somewhat self explanatory. You can find them in the file grid_movement_structure.cpp around lines 2800-3400.

Quote:

Originally Posted by shsreekanth (Post 474305)
2) What does DV_PARAM and DV_VALUE options do? How do you set it for cases other than FFD and HICKS_HENNE?
I am interested specially in the displacement option. Can you tell me how it works? Also could you point me to any documentation material regarding this?

The DV_PARAM options are those that are needed to define each individual design variable. The descriptions can also be found in the config_template in the parentheses after each variable type in the comments. DV_VALUE is the change in magnitude that you specify for each design variable before calling MDC to deform the surface shape and then deform the volume mesh.

Hope this helps,
Tom

Zen November 6, 2014 08:59

Quote:

The DV_PARAM options are those that are needed to define each individual design variable. The descriptions can also be found in the config_template in the parentheses after each variable type in the comments.
Hello everybody,

From what I've understood, DV_PARAM is used to specify the design variables for the shape deformation, that, for example, will be used to compute the gradients by a FD or adjoint formulation. Is this correct?

On the other hand, the DEFINITION_DV option is used to define the design variables for the optimization routine. Does this include that these variables will be used for the calculation of gradients as well (thus making DV_PARAM redundant) ? What is the main difference between DV_PARAM and DEFINITION_DV?

Any help is appreciated,

Thanks,

Z

MarcF November 16, 2016 09:17

Hi,

the Question what is the difference between DV_PARAM and DEFINITION_DV would be of interest for me, too.

In this thread it is said that there has to be an entry in DV_PARAM for every control point:
http://www.cfd-online.com/Forums/su2...formation.html

Although in all available test cases there is only one control point specified.

I want to understand how this works to set the right configurations for an internal multibox problem.

Thanks in advance,
Marc Frankenbach

hlk December 4, 2016 01:38

Quote:

Originally Posted by MarcF (Post 625569)
Hi,

the Question what is the difference between DV_PARAM and DEFINITION_DV would be of interest for me, too.

In this thread it is said that there has to be an entry in DV_PARAM for every control point:
http://www.cfd-online.com/Forums/su2...formation.html

Although in all available test cases there is only one control point specified.

I want to understand how this works to set the right configurations for an internal multibox problem.

Thanks in advance,
Marc Frankenbach

Definition_DV is used by both shape_optimization and gradient calculations (finite_difference, continuous_adjoint) python scripts.

DV_PARAM is used by the SU2_DEF code in combination with the DV_VALUE, DV_KIND, and DV_MARKER options. These options are automatically populated by the DEFINITION_DV options during the operation of the python scripts, where DV_VALUE is set either by the step size of the gradient evaluation or by the design variable values during an optimization.

MarcF December 5, 2016 11:46

Thank you hlk, this helps a lot.:)

So I guess the settings for DV_PARAM in the TestCases are dummy presets to avoid the 'Config parameter not found: DV_PARAM' error?


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