INLET TEST CASE

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Inlet Test Case

This test case couples ROMS and SWAN directly using the Modeling Coupling Toolkit (MCT) library. To run this application the user needs to activate INLET_TEST. It only can be run in distributed-memory (MPI) since the parallel threads are split to run both ROMS and SWAN at the same time. This test illustrates the significance of wave-current coupling. This application and coupling methodology is described in Warner et al. (2008).

This test case models and idealized tidal inlet system. The model domain is a 15x14 km rectangle with a uniform initial depth of 4 m. The model setup parameters are shown in the table below. The domain is separated into two regions: the seaward (top) and back-barrier (bottom) regions. The seaward region is open with radiation conditions on the western, northern and eastern edges. The back-barrier region is enclosed with four walls and is connected to the seaward region through a 2 km wide inlet. The model is forced by a tide and waves. An oscillating water level is imposed on the northern edge with a tidal amplitude of 1 m. Waves are also imposed on the northern edge with a height of 1 m, directed to the south with a period of 10s.


Table 1. Important model parameters: <wikitex>

Model Parameter Variable Value
length, width, depth $Xsize$, $Esize$, $depth$ 15000 m, 14000 m, 4.0 m
number of grid spacings $Lm$, $Mm$, $Nm$ 75, 70, 10
bottom Roughness $z_{ob}$ 0.015 m
time step dt 10 s
simulation steps $Ntimes$ 17280 steps (2 days)
morphology factor $morph\_fac$ 10 (=20 day scaled simulation)
grain size $sd50$ 0.10 mm
settle velocity $w_s$ 11.0 mm s-1
erosion rate $E_o$ 5 x 10-3 kg m-2s-1
critical stress $\tau_{cd}$, $\tau_{ce}$ 0.10 Nm-2
porosity $\phi$ 0.50
bed thickness $bed\_thick$ 10.0 m
northern edge tide $A$, $T_t$ 1.0 m, 12 h
northern edge wave height $H_{sig}$ 2 m
northern edge wave period $T$ 10 s
northern edge wave direction $\theta$ from 0° (from North)

</wikitex>

Below we provide a brief example of the model output.

Figure 1: ROMS output of free surface and barotropic currents at t=0.5 days.


Figure 2: SWAN output of wave height (Hwave, m) and barotropic currents.