Hot-dip galvanization is an ubiquitous process involved in steel production, which consists in covering the alloy with a layer of molten zinc. Gas jets impinge on the surface in order to control the thickness in a procedure called jet wiping, however this causes instabilities that ultimately manifest themselves as ondulations on the final product. Being able to accurately simulate how a jet perturbs the liquid zinc layer on an upward moving substrate is thus essential to obtain a thin and smooth final coating. A 3D spectral solver has been improved and tested, it takes into account the surface tension terms and it features a perfectly matched layer.