Itzï 18.2 is released

19 February 2018 • Laurent Courty

This new version of Itzï improves the stability of the surface-drainage coupling. The part of the code calculating the coupling has been mostly rewritten. The coupling flow between the surface and the drainage is calculated as follows:

  • In case of drainage overflow, the orifice equation is used
  • In case of surface to drainage flow, the coupling flow is calculated by using either the orifice, free weir or submerged weir equation. The equation is chosen according to the relative water surface elevations in the surface and the drainage, and the node crest elevation.
  • If the water is entering the drainage network, the flow is limited to prevent negative depth in the surface model.
  • The coupling flow cannot invert in one time-step. It must spend one time-step at zero. This reduces the oscillations that could occur when the water elevations in both the drainage network and the surface are similar.

This new release is available on the Python package index.

To update your installation to the last version, use the following command:

pip install -U itzi

The Docker image has been updated with the new version.