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U-DaLES
What U-DaLES is
U-DaLES is a free, open-source urban microscale modelling tool for large-eddy simulation of airflow, heat transfer, moisture, and pollutant transport. It runs on Linux, macOS, and Windows Subsystem for Linux, with HPC build guidance, and is delivered as desktop software. Buildings and terrain use triangulated STL surfaces with an immersed-boundary method that conserves mass, momentum, and scalars. Surface energy calculations include shortwave and longwave radiation, multilayer wall conduction, and turbulent sensible and latent heat fluxes. Vegetation is represented as porous drag elements exchanging heat, moisture, and scalars with air. Passive or reactive pollutants can come from point, line, or volume sources, with a basic NOx–O3 chemistry scheme. MPI uses a two-dimensional pencil decomposition for large domains and HPC core counts. The workflow covers preprocessing, solver execution, and post-processing. Results are stored in NetCDF, while Python modules handle preprocessing, geometry, output analysis, visualization, and statistics. The Python package is under active testing and may change.
Who it suits
It suits researchers and HPC users modelling urban airflow, thermal conditions, moisture, and pollutant transport. Users should be comfortable with scientific computing dependencies, cluster workflows, and evolving Python interfaces.
What it does well
- Free and open-source under the GNU GPL
- Models airflow, heat, moisture, and pollutants
- Supports Linux, macOS, and WSL
- MPI targets large HPC domains
- Python tools include 3-D visualization
What to know first
- Python interfaces may change
- Solver requires several build dependencies
- Parallel NetCDF output needs merging
- No lesson library or assessment tools
Verdict
U-DaLES provides a detailed urban simulation workflow with pollutant chemistry, vegetation, surface energy, and HPC parallelism. It is suited to technical modelling work rather than guided teaching, and its evolving Python package requires attention to project updates.
Facts from U-DaLES's own pages
- Air quality
- It supports passive or reactive scalars from point, line, or volume sources and includes a basic NOx–O3 chemistry scheme. · udales.github.io, 7 Oct 2026
- Assessment tools
- No · udales.github.io, 23 Sept 2026
- Building and terrain
- It represents buildings and terrain with a triangulated-surface immersed boundary method that conserves mass, momentum, and scalars. · udales.github.io, 7 Oct 2026
- Data export
- Yes · udales.github.io, 23 Sept 2026
- Data format
- Simulation output is stored in NetCDF files, and parallel output must be merged for convenient visualization and processing. · udales.github.io, 7 Oct 2026
- Delivery mode
- desktop · udales.github.io, 23 Sept 2026
- Dependencies
- The solver prerequisites include CMake, NetCDF-Fortran, a GNU, Intel, or Cray Fortran compiler, MPICH or Open-MPI, and FFTW. · udales.github.io, 7 Oct 2026
- Free plan
- Yes · udales.github.io, 23 Sept 2026
- Input and output tools
- The documented workflow uses MATLAB preprocessing and stores simulation output in netCDF files that can be processed with Python, MATLAB, or other languages. · udales.github.io, 7 Oct 2026
- Intended users
- The model documentation describes uses including urban airflow, heat transfer, pollutant dispersion, and urban air-quality studies at building-resolving resolution. · udales.github.io, 7 Oct 2026
- Lesson library
- No · udales.github.io, 23 Sept 2026
- License
- The public source repository states that uDALES files are licensed under the GNU General Public License. · github.com, 7 Oct 2026
- Offline access
- Yes · udales.github.io, 23 Sept 2026
- Parallel computing
- The model uses MPI with a 2-D pencil domain decomposition and is described as scaling to large domains and core counts on HPC systems. · udales.github.io, 7 Oct 2026
- Platforms
- The installation guide supports Linux, macOS, and Windows Subsystem for Linux; it also documents builds on HPC clusters. · udales.github.io, 7 Oct 2026
- Pollutants
- It supports passive or reactive scalars from point, line, or volume sources and includes a basic NOx–O3 chemistry scheme. · udales.github.io, 7 Oct 2026
- Purpose
- uDALES is an open-source urban microscale modelling tool for large-eddy simulation of airflow, heat transfer, moisture, and pollutant transport. · udales.github.io, 7 Oct 2026
- Python package
- The Python package provides preprocessing, geometry handling, simulation-output analysis, visualization, and statistics modules. · udales.github.io, 7 Oct 2026
- Python package status
- The Python package is under active testing, its interfaces may change, and it is intended to replace the MATLAB toolchain, which the page says will be retired from uDALES v3.0 onwards. · udales.github.io, 7 Oct 2026
- Python tools
- The Python package provides preprocessing, NetCDF output analysis, STL geometry handling, 3-D visualization, and statistics modules. · udales.github.io, 7 Oct 2026
- Support
- The project asks users to report issues or unexpected behavior with the new Python package through the uDALES GitHub issue tracker. · udales.github.io, 7 Oct 2026
- Supported systems
- The model is supported on Linux, macOS, and Windows Subsystem for Linux, and the documentation also provides HPC build instructions. · udales.github.io, 7 Oct 2026
- Surface energy
- Its facet-level surface energy balance includes shortwave and longwave radiation, multilayer wall conduction, and turbulent sensible and latent heat fluxes. · udales.github.io, 7 Oct 2026
- 3D visuals
- Yes · udales.github.io, 23 Sept 2026
Where U-DaLES stands on Freedom251
- Physics Simulation Software#46 of 89