Use the Impedance, Interior Impedance, or Pair Impedance node in time-harmonic analysis to define the input impedance of an external domain, at an interior boundary, or at the boundary between parts in an assembly as the ratio of pressure (or pressure drop) to normal velocity, Zi = p/(n · v) at the boundary. The formulation is following the so-called Ingard-Myers condition. The associated impedance boundary condition is

Enter an input Impedance Zi (SI unit: Pa·s/m).