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shape optimization for RAE2822 with constraint on area

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Old   September 9, 2014, 11:46
Default shape optimization for RAE2822 with constraint on area
  #1
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Hi

I am new to SU2, and tried to optimize RAE2822 with a number of constraints. One is the airfoil Area > initial_Area.
So I set:
OPT_CONSTRAINT= ( LIFT > 0.824 ) * 0.001; ( MOMENT_Z > -0.092 ) * 0.001; ( EQUIVALENT_AREA > 0.07787 ) * 0.001

the errors I got:

------------------------- Exit Success (SU2_CFD) ------------------------

done: 0.8478197895
Moment_Z... done: 0.1048105494
Equivalent_Area... Traceback (most recent call last):
File "/usr/local/SU2/bin/shape_optimization.py", line 130, in <module>
main()
File "/usr/local/SU2/bin/shape_optimization.py", line 75, in main
options.step )
File "/usr/local/SU2/bin/shape_optimization.py", line 113, in shape_optimization
SU2.opt.SLSQP(project,x0,xb,its)
File "/usr/local/SU2/bin/SU2/opt/scipy_tools.py", line 102, in scipy_slsqp
epsilon = 1.0e-06 )
File "/usr/lib/python2.7/dist-packages/scipy/optimize/slsqp.py", line 236, in fmin_slsqp
mieq = len(f_ieqcons(x))
File "/usr/lib/python2.7/dist-packages/scipy/optimize/optimize.py", line 176, in function_wrapper
return function(x, *args)
File "/usr/local/SU2/bin/SU2/opt/scipy_tools.py", line 187, in con_cieq
cons = project.con_cieq(x)
File "/usr/local/SU2/bin/SU2/opt/project.py", line 223, in con_cieq
return self._eval(konfig, func,dvs)
File "/usr/local/SU2/bin/SU2/opt/project.py", line 172, in _eval
vals = design._eval(func,*args)
File "/usr/local/SU2/bin/SU2/eval/design.py", line 132, in _eval
vals = eval_func(*inputs)
File "/usr/local/SU2/bin/SU2/eval/design.py", line 422, in con_cieq
func = su2func(this_con,config,state)
File "/usr/local/SU2/bin/SU2/eval/functions.py", line 94, in function
func_out = state['FUNCTIONS'][func_name]
KeyError: 'EQUIVALENT_AREA'

when I removed the area constraint it works fine.
Can anyone help me with it? I also tried different scaling factor but no help

thanks
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Old   September 21, 2014, 22:39
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Francisco Palacios
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Oops... EQUIVALENT_AREA area is related with the supersonic Area Rule (this is for minimizing the sonic boom in supersonic aircraft design one of SU2 specialties).

Best,
Francisco
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Old   September 22, 2014, 06:41
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Hi thanks a lot Francisco, but then how can I put the constraint on the airfoil area?
note that the constraint is not about the thickness but the total area is no less than the original.
maybe I should use "AREA" instead.
but then the question is the quatity, in the reference area I set (for airfoil) REF_AREA = 1, so can I set the constraint on area as "( AREA > 1 ) * scale" ?
thanks for your help
Quote:
Originally Posted by fpalacios View Post
Oops... EQUIVALENT_AREA area is related with the supersonic Area Rule (this is for minimizing the sonic boom in supersonic aircraft design one of SU2 specialties).

Best,
Francisco
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Old   September 29, 2019, 19:23
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cfdjetman
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I'm doing the exact same case in SU2 6.2. I used AIRFOIL_AREA >0.0778. However, when I can calculate the area of the airfoil of the optimized shape it is typically around 0.0700. I'm not sure how not to violate this constraint.



I had couple of questions.
1. How does the scaling factors on the objective function and constraints affect them? Currently, I just use a scaling factor of 1. What if I used 0.001 instead?
2.Do I need to change the optimizer accuracy accordingly? For e.g, if I used 1e-06 for the drag objective function with scaling factor of 1, do I need to change this to 1e-09 for scaling factor of 0.001?
3. Is there any way of viewing the area of an airfoil in SU2? I currently use the surface file to calculate the airfoil area in MATLAB.
4. As mentioned above, how not to violate the area constraint?


Thanks
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