Editing Lambert W function (section)

=== Porous media ===
The Lambert {{mvar|W}} function has been employed in the field of fluid flow in porous media to model the tilt of an interface separating two gravitationally segregated fluids in a homogeneous tilted porous bed of constant dip and thickness where the heavier fluid, injected at the bottom end, displaces the lighter fluid that is produced at the same rate from the top end. The principal branch of the solution corresponds to stable displacements while the −1 branch applies if the displacement is unstable with the heavier fluid running underneath the lighter fluid.<ref>{{cite journal |last1=Colla |first1=Pietro |year=2014 |title=A New Analytical Method for the Motion of a Two-Phase Interface in a Tilted Porous Medium |journal=PROCEEDINGS, Thirty-Eighth Workshop on Geothermal Reservoir Engineering, Stanford University |volume=SGP-TR-202}}([https://pangea.stanford.edu/ERE/pdf/IGAstandard/SGW/2014/Colla.pdf])</ref>