Use the Far-Field Calculation node to apply the source boundaries for the near-to-far-field transformation and to specify a name for the acoustic far-field variable. This feature allows the calculation of the pressure field outside the computational domain at any distance including phase. The far-field boundary needs to enclose all sources and scatterers.

Enter a Far-field variable name for the far-field acoustic pressure field (the default is pfar).

Select a Type of integral: Integral approximation for r → ∞ (the default) to compute the value in The Far-Field Limit or Full integral to compute The Helmholtz-Kirchhoff Integral Representation.

If required, use symmetry planes in your model when calculating the far-field variable. The symmetry planes have to coincide with one of the Cartesian coordinate planes. For each of these planes, select the type of symmetry check boxes: Symmetry in the x=0 plane, Symmetry in the y=0 plane, or Symmetry in the z=0 plane.

To display this section, click the Show button () and select Advanced Physics Options.

The option Use polynomial-preserving recovery for the normal gradient is selected per default on internal boundaries. This means that the far-field feature automatically uses the polynomial-preserving recovery operator ppr() to get an enhanced evaluation of the normal derivative of the pressure. This increases the precision of the far-field calculation. If you click to clear this check box this removes all instances of the operator from the equations.