pyIECWind

pyIECWind is a modern Python package for generating IEC wind-condition .wnd files for the OpenFAST InflowWind module.

It is designed as a practical successor to legacy IECWind workflows: easier to install, easier to understand, easier to script, and easier for new users to adopt without having to learn historical fixed-format input files first.

If people are still searching for IECWind, IEC wind file generator, or legacy NREL-style extreme wind case tooling, this repository is intended to be the place they can land and immediately use.

Supported IEC Standards

pyIECWind is based on the IEC wind-condition framework from IEC 61400-1.

The current implementation explicitly supports:

• IEC 61400-1 Edition 1 for the normal wind-profile shear exponent option iec_edition = 1
• IEC 61400-1 Edition 3 for the normal wind-profile shear exponent option iec_edition = 3

Important scope note:

• the iec_edition input in this package currently affects the power-law shear exponent selection used in the generated wind files
• the supported extreme wind-condition families are the classic IECWind-style cases: ECD, EWS, EOG, EDC, NWP, and EWM
• this repository does not claim blanket support for every clause, edition, or newer revision of IEC 61400-1

Why This Project Exists

The original IECWind workflow is still useful, but many users now need:

• a package that installs cleanly in modern Python environments
• documentation that explains the case definitions and input style
• an interface that works for both scripted studies and non-expert users
• compatibility with historical IECWind inputs where needed
• output files that can be used directly with OpenFAST InflowWind

pyIECWind keeps the validated IEC case-generation behavior while presenting it through a Python-first package and command-line workflow.

Features

• Generates .wnd files for ECD, EWS, EOG, EDC, NWP, and EWM
• Writes files for OpenFAST InflowWind
• Supports OpenFAST-style input tables with aligned value key - comment rows
• Groups case-family selections under a Cases block
• Includes an interactive wizard for users who prefer prompts over manual editing
• Preserves support for historical keyed and fixed-line input styles
• Ships with tests and a GitHub Actions CI workflow

Installation

Conda

Create the recommended environment:

conda env create -f environment.yml
conda run -n pyiecwind pyiecwind --help

Or install into an existing conda environment:

conda create -n pyiecwind python=3.11 numpy pip -y
conda run -n pyiecwind python -m pip install -e .

Pip

python -m pip install -e .

Quick Start

Generate wind files from the included example:

pyiecwind run examples/sample_case.ipt -o outputs

Write a starter template:

pyiecwind template my_case.ipt

Use the guided workflow:

pyiecwind wizard -o outputs

Default filenames:

• pyiecwind template writes pyiecwind_template.ipt
• pyiecwind run without an explicit file reads pyiecwind.ipt

Example Input

The recommended format is an OpenFAST-style table:

True            si_unit      - True for SI (m, m/s), False for English (ft, ft/s)
40.000          t1           - transient start time [s]
2               wtc          - wind turbine class (1, 2, or 3)
B               catg         - turbulence category (A, B, or C)
0.000           slope_deg    - inflow inclination angle [deg]
3               iec_edition  - IEC edition for alpha (1 or 3)

Case selection is grouped under a Cases section:

ECD             True   [+R, -R]                  - Extreme Coherent Gust with Direction Change. Options: +R, -R, +R+du, +R-du, -R+du, -R-du
EWS             True   [V+12.0, H-12.0]          - Extreme Wind Shear. Options: V+U, V-U, H+U, H-U
NWP             True   [10.0, 23.7]              - Normal Wind Profile. Options: array of hub-height wind speeds in m/s
EWM             True   [50]                      - Extreme Wind Model. Options: 50 or 01, or an array such as [50, 01]

See examples/sample_case.ipt for a complete working file.

Documentation

• QUICKSTART.md
• CHANGELOG.md
• docs/USER_GUIDE.md
• docs/STUDY_EXAMPLE.md
• docs/INPUT_FORMAT.md
• docs/CASE_REFERENCE.md
• docs/MIGRATION.md
• docs/RELEASE_CHECKLIST.md

Project Layout

src/pyiecwind/              package source
examples/                   example input files
docs/                       user and maintainer documentation
tests/                      automated test suite
.github/workflows/ci.yml    GitHub Actions workflow
environment.yml             conda environment definition
pyproject.toml              package metadata

Testing

Run the full test suite:

PYTHONPATH=src:tests python -m unittest discover -s tests -v

On Windows PowerShell:

$env:PYTHONPATH='src;tests'; python -m unittest discover -s tests -v

Notes

• Internal calculations are performed in SI units.
• NWP retains the historical IECWind convention that the embedded speed is interpreted in m/s.
• This package generates inflow files; it does not run OpenFAST itself.
• The supported IEC standard references are currently IEC 61400-1 Edition 1 and Edition 3 as used by the package input and implemented case logic.