DRAIN PIPE PERFORMANCE DETERMINED USING A NON-DARCY FINITE-ELEMENT MODEL

The saturated flow towards drain pipes wrapped with voluminous envelop e was investigated by means of a two-dimensional finite element model for non-Darcy flow. Special attention was given to the flow in the imm ediate vicinity of the drain pipe which may cause the movement of soil particles and, as a result, clogging of the envelope. Non-linear elem ents were used for a better representation of the geometry around the drain and for more accurate prediction of hydraulic heads owing to non linear interpolation. Results showed the influence of non-Darcy flow o n the head losses near the drain and on the water table heights for va riable envelope permeability.