# Irregular wave normal incidence¶

Figure: (left) snapshot of surface elevation, (middle) vorticity field, (right) mean current field

The following sections wil be modified in “input.txt” for this example. The domain setup was defined in Basics for model setup.

Set a descriptive title for your simulation:

```!-----TITLE-----
TITLE = rip_2D
```

Add an irregular wavemaker in a water depth of 13.0 m located 425.0 m from the left boundary with the following characteristics:

```!-----WAVEMAKER-----
WAVEMAKER = WK_IRR
DEP_WK = 13.0
Xc_WK = 425.0
Yc_WK = 0.0
FreqPeak = 0.1
FreqMin = 0.03
FreqMax = 0.5
Hmo = 1.0
GammaTMA = 5.0
ThetaPeak = 0.0
Sigma_Theta = 10.0
```

(refer to Wave-maker specification for parameter definitions)

Set the periodic boundary condition to TRUE:

```!-----PERIODIC BOUNDARY CONDITION-----
PERIODIC = T
```

Set the sponge layer width to 60 m:

```!-----SPONGE LAYER-----
DIFFUSION_SPONGE = F
FRICTION_SPONGE = T
DIRECT_SPONGE = T
Csp = 0.0
CDsponge = 1.0
Sponge_west_width =  0.0
Sponge_east_width =  60.0
Sponge_south_width = 0.0
Sponge_north_width = 0.0
```

(refer to Sponge Layers for parameter definitions)

Set the friction coefficient to 0.002:

```!-----PHYSICS-----
Cd = 0.002
```

Keep the default values for the `NUMERICS`.

Set the minimum depth for wetting and drying to 0.01:

```!-----WET-DRY-----
MinDepth = 0.01
```

Set the viscosity breaking scheme to FALSE:

```!-----BREAKING-----
VISCOSITY_BREAKING = F
```

(refer to Example: Breaking for parameter definitions)

Set the wave average parameters to the following:

```!-----WAVE AVERAGE-----
T_INTV_mean = 50.0
```

Set the following output parameters to TRUE:

```!-----OUTPUT-----
ETA = T
U = T
V = T
Umean = T
Vmean = T