INLET TEST CASE

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.

Files to run this test case can be downloaded here.

Table 1. Important model parameters:

Model Parameter	Variable	Value
length, width, depth	Xsize, Esize, hmax	15000 m, 14000 m, 4.0 m
number of grid spacings	Lm, Mm, N	75, 70, 10
bottom Roughness	Zob	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	Wsed	11.0 mm s-1
erosion rate	Erate	5 x 10-3 kg m-2s-1
critical stress	tau_cd, tau_ce	0.10 Nm-2
porosity	poros	0.50
bed thickness	bed(:, :, :, ithck)	10.0 m
northern edge tide	A, Tt	1.0 m, 12 h
northern edge wave height	Hsig	2 m
northern edge wave period	T	10 s
northern edge wave direction	θ	from 0° (from North)

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.