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Add Eames tower shadow model to AD15 #645

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merged 11 commits into from
Jan 22, 2021

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andrew-platt
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@andrew-platt andrew-platt commented Jan 21, 2021

This pull request is ready for merging. Merge this after #643

Feature or improvement description
This pull request adds the Eames tower shadow model as an option in addition to the Powles model.

Impacted areas of the software
This only affects the available tower shadow model options used within AD15 and the AD15 input file format. This adds a new column to the tower properties table for the TI value to use with the Eames model.

Additional supporting information
This model was developed with the University of Virginia under the SOAR program. They completed testing of the model and set reasonable limits for the tower TI values.

Preliminary figures for comparison
Qualitatively, the Eames model returns something that is similar to the Powles model. For the testing, a TI value of 0.1 is used along the entire tower for the Eames model, with degrees of freedom to off in ElastoDyn. The plots below show the Fx, My, and Mz for blade 1 as a function of azimuth (0 azimuth is blade 1 pointed straight up).

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@ebranlard ebranlard left a comment

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It looks good to me. Good job updating the documentation as well, and +1 for a couple of condensed error checking :)

I see this as an opportunity to start the theory manual. Maybe just adding a theory.rst with a content along these lines?


.. _AD_theory:

AeroDynTheory
==========

This theory manual is work in progress, please refer to the AeroDyn manual for more details. 


.. _AD_twr_shadow

Tower shadow models
~~~~~~~~~~~~~~~

Powles tower shadow model (**TwrShadow=1**) is given by:

.. math::

         u_{TwrShadow} = - \frac{TwrCd}{  \sqrt{\overline{r}}  } \cos( \pi/2 \overline{y}/\sqrt{\overline{r}})^2
        ,\qquad
         \overline{r} = sqrt{ \overline{x}^2 + \overline{y}^2 } }

Eams tower shadow model (**TwrShadow=2**) is given by:

.. math::

          u_{TwrShadow} = -\frac{C_d}{ TI \overline{x} \sqrt{2 \pi }  }   \exp{ -1/2 ( \overline{y} / (TI \overline{x}) )^2 } 

@andrew-platt andrew-platt force-pushed the f/AD15_TowerShadow branch 4 times, most recently from 8e23324 to 2ff9c6d Compare January 21, 2021 23:02
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@jjonkman jjonkman left a comment

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In input.rst, it says, "Update this statement after testing!!!!!!*" But the comment section of the pull request says testing was completed. Should this statement be deleted?

Looking at the source code, it looks like 0.05 < TI <= 0.4 is recommended.

Otherwise, everything else looks good and matches the implementation plan.

@andrew-platt
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@jjonkman, good catch. I forgot about that comment in the docs.

@andrew-platt andrew-platt merged commit 08ec00a into OpenFAST:dev Jan 22, 2021
@andrew-platt andrew-platt deleted the f/AD15_TowerShadow branch January 22, 2021 20:36
@rafmudaf rafmudaf mentioned this pull request May 11, 2021
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4 participants