<p class="p1"Asymmetric run-back flow developing during annular jet wiping in a wire coating process. A high-speed gas jet is used to regulate the thickness of the liquid film entrained by themoving wire; however, unlike planar jet wiping, the annular geometry cannot remain perfectly axisymmetric because the jet must contain an opening through which the wire can be continuously inserted and replaced. This broken symmetry generates azimuthal interfacial waves and uneven liquid redistribution around the wire. The resulting disturbances interact with the wiping jet and can amplify coating non-uniformities in the final deposited layer. Controlling such interfacial instabilities is essential for achieving homogeneous wire coatings.

VKI Album of Fluid Motion, page 33