• InfoWorks ICM

Adding porous walls and polygons

Add porous objects that represent walls with a specified porosity and height.

Step-by-step guide

Porous walls and polygons represent walls with a specified porosity and height that are used during the 2D simulation process. A porous wall collinear with the boundary of a 2D zone overrides the boundary condition. It is possible to set parameters for the porous wall object that results in the full or partial removal of the wall during a simulation.

This example has a selection of porous walls and porous polygons that have varying properties.

In the GeoPlan, examples of porous walls and porous polygons, with the first porous polygon selected and highlighted in red.

These properties can be viewed or changed in the Properties window.

  1. Open the Properties window of the first porous polygon.

The Properties window for the selected porous polygon.

  1. Note the Porosity value.

This must be a value between 0 and 1, where 0 is impermeable and 1 is fully porous, meaning it has no impact on the flow. As an example, a low porosity in the range of 0.05 - 0.2 may be used to represent a building.

  1. Expand the Crest level drop-down to choose from 3 options: Infinite, Height, and Level.

This is the point up to which the porosity applies—above this, there will be no effect.

  1. Expand the Remove wall during simulation drop-down, which also has 3 options: Never, Fully, or Partially.

For the Partially option, only faces of the wall meeting the criteria are removed. This option can be used to simulate wall collapse.

  1. Select No rainfall to apply no rainfall within the polygon—an option only available for porous polygons.

To best demonstrate the effect of these objects, in this example, a simulation is run with the porous walls and polygons included.

In a running rainfall simulation, with water represented in blue with red flow arrows, more water flows through the polygons with greater porosity values, and builds up to a higher depth behind the polygon with lower porosity.

As the water passes through the objects, the porosity takes effect. Those with lower porosity have a higher depth building up behind them and are the first to be removed when the height threshold is reached.