feat: wind-turbine noise — apparent sound power & tonal audibility (IEC 61400-11) (#146)
* docs: implementation plan for wind-turbine noise (IEC 61400-11) PR-B2
* feat(wind-turbine): apparent sound power + tonal audibility chain (IEC 61400-11)
Add wind_turbine_noise.py: slant_distance/apparent_sound_power_level (Formula
26) and wind_turbine_tonality (Formulae 30-34) returning a
WindTurbineTonalityResult with .plot(). Named to avoid colliding with the
existing ISO 1996-2 critical_bandwidth/tonal_adjustment/tonal_audibility; the
K_T rating reuses the ISO 1996-2 tonal_adjustment already in the library.
* feat(wind-turbine): conformance domain (IEC 61400-11), 168/168
* feat(wind-turbine): tonal-audibility figure (x4 variants)
* docs(wind-turbine): EN guide + site EN/ES, api-reference, indices, sidebar
* fix(wind-turbine): correct low-frequency band and non-adjacent tone lines
Two correctness fixes from review, against IEC 61400-11:2012+A1:2018:
- The 20-70 Hz candidate uses the fixed absolute 20-120 Hz critical band, not
a band centred on the tone frequency (subclause 9.5.3). The previous
|f - fc| <= CBW/2 window only coincided with 20-120 Hz at fc = 70.
- Tone lines need not be contiguous with the peak. A1:2018 struck "adjacent";
every line in the critical band above the tone threshold and within 10 dB of
the peak is a tone. The Hanning /1.5 correction is now applied per contiguous
run rather than once for the whole set, so separated tones are summed
correctly.
Add tests for a low-frequency tone (excluding sub-20 Hz lines) and for two
separated tone lines.
* fix(wind-turbine): review pass — validation, shared band helper, plot color
- wind_turbine_tonality: validate strictly-increasing and uniformly-spaced
frequencies (the narrowband-spectrum precondition of Formulae 30-34)
- extract shared _critical_band_edges() so the plots use the fixed 20-120 Hz
low-frequency band instead of fc±CBW/2 (matches the classification logic)
- correct the WindTurbineTonalityResult docstring return type
- distinct masking-level line colour in the generated figure (no longer
blends with the grid)
- regenerate the 4 wind_turbine_tonality figure variants
- add regression tests for the frequency-axis validation
* fix(wind-turbine): address CodeRabbit review
- tighten the uniform-spacing tolerance to 1e-3·df so a near-miss axis (e.g.
2,2,2.4 Hz) that would bias df/ENBW is rejected; add a near-miss test
- fix a duplicate-keyword TypeError in plot_epnl / plot_wind_turbine_tonality
when a caller passes lw/label/color; merge defaults so caller values win;
add a plot-kwargs regression test
- remove the unused _AUDIBILITY_REPORT_LIMIT constant (the multi-spectrum
'No relevant tones' reporting rule is out of scope); is_audible stays ΔL_a>0
per IEC 61400-11 §9.5.8 ('a tone is audible if the tonal audibility is above
0 dB')
- add unit=dB to the apparent-power conformance row for table consistency
- document band_levels as background-corrected and the narrowband-spectrum
constraints in api-reference; make the guide code examples self-contained
- markdownlint-clean the wind-turbine plan doc