Moiré patterns of the membrane analogy for ground-water movement applied to multiple fluid flow

In the membrane analogy for flow through porous media, contour lines of a deflected membrane represent either streamlines or equipotential lines. The membrane was used by Prandil [1903] to solve torsion problems. Hansen [1952] gave a description of the application of the analogy to solve the flow patterns resulting from systems of sources and sinks. Multiple fluid flow through porous media may be treated by considering a suitable distribution of sources and sinks [de Josselin de Jong, 1960] and therefore the membrane analogy is also applicable to this problem.