BEM numerical simulation of coupled heat and moisture flow through a porous solid

The problem of unsteady coupled moisture and heat energy transport through a porous solid is studied numerically using singular boundary integral representation of the governing equations. The integral equations are discretized using mixed-boundary elements and a multidomain method also known as the macro-elements technique. Two discretization models over time are presented, i.e. constant and linear interpolation in time. Numerical simulations were performed for the benchmark problems of moisture uptake within a semi-infinite region and for the drying out of a layer. Non-uniform grids of increasing mesh density were employed to ensure accurate solutions. Satisfactory agreement is obtained with benchmark results, especially when using the linear in time numerical model.