The Fluid Dynamics node incorporates physically based fluid simulations into the framework based on an Eulerian (grid based) approach. It generates a velocity field (vector grid channel) which represents motions of a single-phase fluid (Air for example).

This velocity field can be used by any channel to advect its content according to the fluid motion and enables you to therefore simulate smoke, fire, explosions and similar gaseous media moving through air in a physically correct manner.