Simulation Defaults
All hardcoded simulation constants are defined in run_anuga/defaults.py. These values are used when a scenario does not specify an explicit override.
Constants reference
Structure parameters
| Constant |
Value |
Description |
BUILDING_BURN_HEIGHT_M |
5.0 |
Height (metres) added to the DEM where building footprints are rasterised. This effectively creates walls that prevent water from flowing through buildings. |
BUILDING_MANNINGS_N |
10.0 |
Manning's roughness coefficient applied to building footprint polygons. A very high value that impedes flow. |
DEFAULT_MANNINGS_N |
0.04 |
Default Manning's roughness applied to all areas not covered by explicit friction polygons. Typical of light grass or bare soil. |
Rainfall conversion
| Constant |
Value |
Description |
RAINFALL_FACTOR |
1.0 x 10^-6 |
Conversion factor from mm/hr rainfall intensity to m/s, which ANUGA uses internally. Applied as the factor parameter in Polygonal_rate_operator. |
Domain evolution
| Constant |
Value |
Description |
MINIMUM_STORABLE_HEIGHT_M |
0.005 |
Minimum water depth (metres) stored in SWW output files. Cells with less water than this are treated as dry in the output. |
MIN_ALLOWED_HEIGHT_M |
1.0 x 10^-5 |
Minimum water depth (metres) used during velocity extrapolation in post-processing. Prevents division by near-zero depth. |
MAX_YIELDSTEPS |
100 |
Maximum number of yield steps during domain evolution. The yield step interval is duration / MAX_YIELDSTEPS or MIN_YIELDSTEP_S, whichever is larger. |
MIN_YIELDSTEP_S |
60 |
Minimum yield step interval in seconds. ANUGA will not write output more frequently than once per minute. |
MAX_YIELDSTEP_S |
1800 |
Maximum yield step interval in seconds (30 minutes). Even for very long simulations, output is written at least this often. |
Mesh generation
| Constant |
Value |
Description |
MAX_TRIANGLE_AREA |
10_000_000 |
Maximum triangle area (m^2) in the mesher configuration. Acts as an upper bound for the coarsest possible mesh. |
Post-processing
| Constant |
Value |
Description |
K_NEAREST_NEIGHBOURS |
3 |
Number of nearest neighbours used when interpolating ANUGA mesh results to regular GeoTIFF grids. |
| Constant |
Value |
Description |
DEFAULT_MESHER_EXE |
/opt/venv/hydrata/bin/mesher |
Default path to the mesher binary used for adaptive mesh generation. Override with the MESHER_EXE environment variable. |