Comments on "The Depth-Dependent Current and Wave Interaction Equations: A Revision"

TL;DR

This paper critiques existing wave-current interaction equations, highlighting their inconsistencies over sloping bottoms and proposing that alternative formulations using quasi-Eulerian velocity are more reliable for 3D modeling.

Contribution

It identifies flaws in current depth-dependent momentum equations and advocates for using quasi-Eulerian velocity formulations for accurate wave-current interaction modeling.

Findings

Current equations can produce erroneous flows outside surf zones.

Inconsistencies may stem from different averaging operators.

Quasi-Eulerian velocity based equations are more suitable.

Abstract

Equations for the wave-averaged three-dimensional momentum equations have been published in this journal. It appears that these equations are not consistent with the known depth-integrated momentum balance, especially over a sloping bottom. These equations should thus be considered with caution as they can produce erroneous flows, in particular outside of the surf zone. It is suggested that the inconsistency in the equations may arise from the different averaging operators applied to the different terms of the momentum equation. It is concluded that other forms of the momentum equations, expressed in terms of the quasi-Eulerian velocity, are better suited for three dimensional modelling of wave-current interactions.