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Optimization with OpenFOAM® Group Forum: All users which use OpenFOAM® for optimization are welcome!
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TOPIC: starting a discussion
#169
starting a discussion 1 Year, 2 Months ago Karma: 0
Hey,
nice to see you in this group
Maybe this is a good opportunity for discussing what every one is doing with OpenFOAM®®.
At the last "OpenFOAM®® Stammtisch" no one except of Daria and me were doing optimization.
It might be interesting to see where the users are who optimize with OpenFOAM®®.
Anne Lincke
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Last Edit: 2011/03/02 09:23 By AnneLincke.
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#176
Re:starting a discussion 1 Year, 2 Months ago Karma: 0
Hi, I'm interested in learning more about the best practice for optimization using OpenFOAM®. Basically I have my OpenFOAM® model with some kinetic and transport parameters that I want to fit to experimental data (I'm working in batteries/fuel cells). So far I've been able to implement some fitting algorithms by combining the SciPy optimization tools (via python), but I'm not entirely convinced that this is the way to go.

What is everybody else here using optimization for?
Ben Kenney
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#178
Re:starting a discussion 1 Year, 2 Months ago Karma: 0
Hey Ben,

thank you for joining this group and starting a discussion.
I am using OpenFOAM® for optimizing pressure loss and uniformity for a cabin air inlet of aircrafts.
Optimization is done via solving the adjoint Navier Stokes equations and computing sensitivities which indicate how to morph/change the surface shape of the object in order to obtain an improvement.

The adjoint solver is not included in the standard OpenFOAM® version, that is why I am using a pice of code which was written by someone else.

What does the SciPhy optimization tool do? What is the basic theory for your optimization and what do you want to optimize (which object function)?
Anne Lincke
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#179
Re:starting a discussion 1 Year, 2 Months ago Karma: 0
SciPy optimization has a whole bunch of optimization algorithms, like Newton-conjugate gradient method, simplex methods etc (docs.scipy.org/doc/scipy/reference/optimize.html). It's a python interface. So basically what I've done is I made a curve fitting routine that fits my OpenFOAM® input parameters (diffusion coefficients and reaction rate constants, I have 5 of them) to experimental data by minimizing an objective function (in this case the sum of squares between by openFOAM model output and my experimental data). The algorithms are similar to what matlab offers (except scipy is free).

So the code that you use to calculate the sensitivities, is that built into openFOAM? I'd be interested in taking a look at that. I've never had any luck with gradient based optimization methods, I've only been able to get the simplex methods to work but those are quite inefficient and they don't give you the confidence intervals.
Ben Kenney
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#180
Re:starting a discussion 1 Year, 2 Months ago Karma: 1
have you read An Efficient Adjoint-Based Method Applied on Vehicle. Aerodynamic Optimisation by Eugene De Villiers
www.opensourcecfd.com/conference2008/200...2e9db00b8b978b532798

the discussion on cfd-online www.cfd-online.com/Forums/openfoam-solvi...r-flow-problems.html was not fruitful
Guido Aselmann-Brinkmann
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#181
Re:starting a discussion 1 Year, 2 Months ago Karma: 1
Hi,
An Efficient Adjoint-Based Method Applied on Vehicle. Aerodynamic Optimisation. "Eugene de Villiers" www.opensourcecfd.com/conference2008/200...2e9db00b8b978b532798
This was done with OF, but it is a commercial presentation when Eugene worked for ICON CFD, now Eugene is at engys
Guido Aselmann-Brinkmann
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