  A significant computational expense and source of numerical errors in front
tracking is the remeshing of the triangulated front, required due to distortion
and compaction of the front following the Lagrangian advection of its vertices.
Additionally, in classic front tracking, the remeshing of the front mesh is
required not only due to the deformation of the front shape, but also because
the vertices of the front are translated in the direction tangential to the
front, induced by the front advection. We present the normal-only advection
(NOA) front-tracking method with the aim of preventing the tangential motion of
the front vertices and the associated vertex clustering, in order to reduce the
number of remeshing operations required to retain a high-quality triangulated
interface. To this end, we reformulate the velocity used to advect the front at
each discrete front-vertex position. The proposed method is validated and
tested against the classic front-tracking method, comparing volume
conservation, shape preservation, computational costs, and the overall need for
front remeshing, as well as experimental results for canonical interfacial
flows. The presented results demonstrate that the NOA front-tracking method
leads to a typical reduction of remeshing operations by 80 % or more compared
to the classic front-tracking method for well-resolved cases, and results in a
smoother front mesh, which is essential for an accurate representation of the
geometrical properties of the front. The volume conservation error is reduced
by approximately one order of magnitude with the proposed method compared to
the classic front-tracking method, at a similar computational cost.
