Porous baffle and porous media
 

I'm trying to study the flow patterns in a wide-angle diffuser in which separation occur. To prevent or delay it one can use gauze screens and honeycomb that are represented with the help of porous baffles and porous medias.

Do the parameters named "porosity" for porous medias and porous baffle correspond to the ratio (effective section area)/(real section area, i.e. without the device)?

Thanks