A new method to analyse properties such as pressure loss of open-cell foams is given by the rise in computational speed, which makes it possible to handle even the flow within these structures with conventional CFD methods. In the present study air flows through several structures have been calculated explicitly using the standard Navier-Stokes equations. The structures comprised reconstructed tomographic data obtained by means of MRI as well as model structures of various complexity. Numerical determination and variation of tortuosity by closing structure windows provided a possibility to match the pressure drop calculated in modelled structures with experimental literature data. (C) 2009 Elsevier Ltd. All rights reserved.