imod.evaluate.stability_constraint_wel#
- imod.evaluate.stability_constraint_wel(wel, top_bot, porosity=0.3, R=1.0)[source]#
Computes sink/source stability constraint as applied in MT3D for adaptive timestepping (Zheng & Wang, 1999 p54).
\[\Delta t \leq \frac{R\theta }{\left | q_{s} \right |}\]For the WEL package, a flux is known beforehand, so we can evaluate beforehand if a flux assigned to a cell will necessitate a small timestap, thereby slowing down calculations.
Returns a ipf DataFrame that includes a column for the specific discharge and resulting minimum timestep.
- Parameters:
wel (pd.DataFrame) – pd.DataFrame that defines a WEL package. Minimally includes x, y, layer and Q column.
top_bot (xr.Dataset of floats, containing 'top', 'bot' and optionally) – ‘dz’ of layers. Dimensions must be exactly
("layer", "y", "x")
.porosity (float or xr.DataArray of floats, optional (default 0.3)) – If xr.DataArray, dimensions must be exactly
("layer", "y", "x")
.R (Retardation factor, optional (default)) – Only when sorption is a factor.
- Returns:
wel – dt (minimum timestep) columns
- Return type:
pd.DataFrame containing addition qs (specific discharge) and