  Pure advection of a conservative scalar is relevant to several applications
including two-phase flow. Successful numerical schemes must capture the sharp
interface between the phases while maintaining a smooth (wrinkle-free)
interfacial contour. Among other methods, algebraic schemes that are based on
the addition of an extra artificial interface compression term to the scalar
transport equation have gained recent popularity (e.g., OpenFOAM; porous
media). While the approach offers unique flexibilities in spatiotemporal
discretizations, common numerical treatments result in the wrinkling of the
interface. In this short note, an easy-to-implement solution to this problem is
presented.
