Closure Challenge v2 — licensing

This dataset aggregates material under two different licenses. Which terms
apply depends on which case directory the file sits in.

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A. CC-BY-4.0
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Applies to: alpha_05_4071_2024, alpha_05_4071_4048, alpha_15_13929_2024,
alpha_15_13929_4048, AR_1_Ret_360, AR_3_Ret_360, AR_14_Ret_180,
NASA_2DWMH, NASA_2DZP, NASA_2DN00, NASA_ASJ, NASA_FaithHill,
and every case under data/train/ and data/validation/.

The training and validation sets are drawn from the same upstream sources as
the CC-BY-4.0 test cases: the Xiao et al. parametric periodic-hill database,
the Vinuesa duct database, and the CBFS and periodic-hill reference flows of
the v1 benchmark. None of them derive from ERCOFTAC kbwiki material, so none
fall under section B.

Upstream sources are public-domain or CC-BY: NASA Turbulence Modeling
Resource, the Vinuesa duct database, and the Xiao parametric periodic-hill
database. Full text: https://creativecommons.org/licenses/by/4.0/

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B. CC-BY-NC-SA-4.0
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Applies to: ERCOFTAC_AhmedBody25, ERCOFTAC_WingBodyJunction.

These are curated extracts of ERCOFTAC kbwiki material (Classic Collection
case082; DNS 1-6) and inherit the upstream CC-BY-NC-SA-4.0 terms, including
the non-commercial and share-alike conditions.
Full text: https://creativecommons.org/licenses/by-nc-sa/4.0/

The raw upstream reference archives under data/high_fidelity_data/ follow the
license of the case they belong to, per the same split.

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C. Code
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Extraction, plotting, and run scripts (*.py, *.sh) are MIT licensed.
See LICENSE-CODE in the accompanying code repository.

Per-case source attribution is in SOURCES.md in the code repository.