Mesh adaptive finite element formulation for moisture transfer in materials with a critical moisture content

Wetting or drying of most open porous building materials is characterized b y a sharp moving waterfront. Due to the high moisture gradients at the wate rfront, an accurate finite element simulation requires a very fine mesh. To reduce computational costs a mesh adaptive method based on the Arbitrary L agrangian Eulerian (ALE) technique is proposed. To continuously relocate th e nodes on the computational domain a remesh-indicator is equally distribut ed. In problems of water imbibition or drying of open porous building mater ials specific attention has been paid to the zone of critical moisture cont ent. To this extent the traditional jump-based indicator, quantifying the j ump of a selected state variable, has been modified into an area-based reme sh-indicator. An error analysis of an academic example shows that the area- based indicator is superior to the jump-based one. To illustrate the capabilities of the remeshing method based on an area-bas ed indicator, one and two-dimensional examples of water imbibition of ceram ic brick and drying of cellulose fibre cement are included. Copyright (C) 1 999 John Wiley & Sons, Ltd.