Some remarks on the acoustic parameters of sharp-edged porous media

This work revisits some numerical experiments by Smeulders et al, [Smeulders DMJ, Van Hassel RR, Van Dongen MEH, Jansen JK. Int. J. Eng. Sci. 1994;32(6):979]. It concerns the acoustic properties of two-dimensional porous media whose pore surface is rugged, Contrary to what is inferred by Smeulders et al., we discover that Johnson's shape factor, M, remains finite and is in the order of unity if the surface is not cusped. However, in agreement with Smeulders et al,, M --> + infinity when the pore surface has a sharp edge whose angle tends to zero. (C) 1998 Elsevier Science Ltd. All rights reserved.