**4. Results**

We proceeded in two steps. First, we used a numerical method to find values of permeability for fibrous porous media based on regular hexagonal array of cylinders. The numerical results thus obtained were compared with the analytical results found in the literature. In the second step, we used the numerical method to find values of permeability coefficient for the wool fibre web, packaging board and sandstone samples. These results were compared with the experimental results obtained by using the PMD (Koivu et al., 2009a; Koivu et al., 2009b).
