Elastic membrane
= Elastic membrane
{title2=$\eta$}
An <elastic membrane> is a thin deformable sheet whose transverse restoring force is supplied by in-plane tension. For uniform tension $T$ and <mass> per <area> $m$, a two-dimensional small-displacement model has $m\eta_{tt}=T\eta_{xx}-[p]$, where the <pressure> jump is defined from the lower <fluid> to the upper <fluid>. <Fluid> loading modifies its traveling modes through the <acoustic wave on a tensioned massive membrane>.