  We study fluid flow at the interfaces between elastic solids with randomly
rough, self-affine surfaces. We show by numerical simulation that elastic
deformation lowers the relative contact area at which contact patches percolate
in comparison to traditional approaches to seals. Elastic deformation also
suppresses leakage through contacts even far away from the percolation
threshold. Reliable estimates for leakage can be obtained by combining
Persson's contact mechanics theory with a slightly modified version of
Bruggeman's effective-medium solution of the Reynolds equation.
