The Level Set in Porous Media (ls) interface (), found under the Mathematics>Moving Interface branch () when adding an interface, is used to track moving interfaces in fluid-flow through porous media models by solving a transport equation for the level set function. Simulations using the Level Set in Porous Media interface are always time dependent since the position of an interface almost always depends on its history.

The main node is the Porous Medium Level Set Model feature, which adds the level set equation and provides interfaces for defining the level set properties, the velocity field and the porosity of the porous matrix.

When this physics interface is added, the following default nodes are also added in the Model Builder — Porous Medium, No Flow (the default boundary condition), Initial Values, and Initial Values, Fluid 2. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions. You can also right-click Level Set in Porous Media to select physics features from the context menu.

The rest of the settings are the same as for the Level Set interface.