15.19. Swash

This test case addresses wave dynamics on a gently sloping laboratory beach (Globex experiment), using a wave-resolving configuration. The simulation is compared in Marchesiello et al. (2021) against GLOBEX experiments B2 and A3 performed in 2012 in the Scheldt flume of Deltares (Delft, the Netherlands), and described in Michallet et al. (2014). The flume is 110 m long and contains a solid beach of 1:80 slope with its toe at 16.6 m from the wave maker. Experiments are run with a still water depth of 0.85 m and shoreline at x = 84.6 m. Second-order bichromatic waves (B2) are generated at the offshore boundary, with shore normal direction. The grid spacing is dx=1 cm with 10 vertical levels evenly spaced between the free surface and bottom. A simulation with 20 levels gives similar results, while the solution is moderately degraded (mostly in higher moments) with coarser horizontal resolution (dx=3, 6 and 12 cm), which shows good convergence properties. The model time step is dt = 0.15 ms. The minimum depth is 1 mm on the shore, the position of which varies with the swash oscillation, relying on the wetting-drying scheme in CROCO. For bottom drag, the logarithmic law of the wall is used with roughness length \(z_0 = 0.0625\) mm.

Marchesiello P., F. Auclair, L. Debreu, J.C. McWilliams, R. Almar, R. Benshila, F. Dumas, 2021: Tridimensional nonhydrostatic transient rip currents in a wave-resolving model. Ocean Modelling, 163, 101816.

Michallet H., B. G. Ruessink, M.V.L.M. da Rocha, A. de Bakker, D. van der A, et al.. GLOBEX: Wave dynamics on a shallow sloping beach. HYDRALAB IV Joint User Meeting, Lisbon, July 2014, Jul 2014, Lisbonne, Portugal.

# define SWASH

CPP options:

# define SWASH_GLOBEX_B2
# undef  SWASH_GLOBEX_A3
# undef  OPENMP
# undef  MPI
# define SOLVE3D
# define AVERAGES
# define NBQ
# define NBQ_PRECISE
# define WAVE_MAKER
# define UV_ADV
# define UV_HADV_WENO5
# define UV_VADV_WENO5
# define W_HADV_WENO5
# define W_VADV_WENO5
# define GLS_MIXING_3D
# define NEW_S_COORD
# define ANA_GRID
# define ANA_INITIAL
# define ANA_SMFLUX
# define ANA_STFLUX
# define ANA_SSFLUX
# define ANA_SRFLUX
# define ANA_SST
# define ANA_BTFLUX
# define OBC_WEST
# define OBC_SPECIFIED_WEST
# define FRC_BRY
# define ANA_BRY
# define Z_FRC_BRY
# define M2_FRC_BRY
# define M3_FRC_BRY
# define T_FRC_BRY
# define WET_DRY
# define NO_FRCFILE

Settings :

Results :

SWASH results : Velocity and elevation