The Incident Pressure Field node is a subnode to all nonreflecting boundary conditions (plane, cylindrical, and spherical wave radiation). From the Physics toolbar, add to Plane Wave Radiation, Spherical Wave Radiation, or Cylindrical Wave Radiation nodes. Three options exist for transient models: Plane wave (monochromatic) (the default), Modulated Gaussian pulse, and User defined.

The same options apply as for the incident fields as for the Background Pressure Field (for Transient Models) feature.

The same options apply as for the incident fields as for the Background Pressure Field (for Transient Models) feature.

For User defined enter an expression that defined the incident wave. The incident pressure field needs to be defined as a traveling wave of the form

where ω is the angular frequency and k is the wave vector. The function f is any function, for example, a sine function. This spatial and temporal dependency is a requirement for the radiation boundary condition to work properly.