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.

# 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