  Numerical solvers of the two-dimensional (2D) shallow water equations
(2D-SWE) can be an efficient option to predict spatial distribution of velocity
fields in quasi-steady flows past or throughout hydraulic engineering
structures. A second-order finite volume solver (FV2) spuriously elongates
small-scale recirculating eddies within its predictions, unless sustained by an
artificial eddy viscosity, while a third-order finite volume (FV3) solver can
distort the eddies within its predictions. The extra complexity in a
second-order discontinuous Galerkin (DG2) solver leads to significantly reduced
error dissipation and improved predictions at a coarser resolution, making it a
viable contender to acquire velocity predictions in shallow flows. This paper
analyses this predictive capability for a grid-based, open source DG2 solver
with reference to FV2 or FV3 solvers for simulating velocity magnitude and
direction at the sub-meter scale. The simulated predictions are assessed
against measured velocity data for four experimental test cases. The results
consistently indicate that the DG2 solver is a competitive choice to
efficiently produce more accurate velocity distributions for the simulations
dominated by smooth flow regions.
