In many applications plates or impervious screen layers are perforated. That means there is a fraction of motion given by the flow through the

perforation of the plate. This is done by using the `perforation`

keyword in the definition of the related infiniteLayers class.

Usually, a plate or mass layer is described by a transfer impedance . When the layer is in addition perforated and this perforation is described by the transferimpedance this can by implemented by assuming that both transfer impedances are working in parallel.

Z_{p,perf}=\left(\frac{1}{Z_p}+\frac{1}{Z_{perf}}\right)^{-1}=\frac{Z_p Z_{perf}}{Z_{p} + Z_{perf}}

A limp mass layer with and a purely resistive perforation reads as:

Z_t =\frac{j\omega m' R_s}{j\omega m'+R_s}

Details of implementation and examples can be found in the pyva documentation.

Installation update from the github page or with:

`pip install pyva-toolbox`