Significant wave height distribution Hmo(x,y) over the entire computational
grid (xxx_Hs.grd) The significant wave height is calculated as four times
standard deviation of the water-surface elevation over the duration of the
synthesized or input time record, i.e.,
1 ts 2
∑ η ( x, y, t ) - η ( x, y)
H mo ( x, y) = 4
2
N - 1 ts -tw
For regular waves, the wave height can be obtained from the significant wave
height as Hmo/ 2 . It should noted that there could be differences between the
significant wave height estimated from the standard deviation of the time
record and those obtained using zero-crossing analysis especially for highly
asymmetric waves in shallow water.
The time-averaged or mean current uα (x,y) over the entire computational
domain (xxx_uv.grd).
1 ts
∑ uα ( x, y, t )
uα ( x, y ) =
N ts -tw
The time-averaging procedure is also carried out over the duration of the
synthesized or input time record.
Time Series Output
Time series of the water-surface elevation η(t) and two components of the
horizontal velocity uα(t), vα(t) at specified (x,y) locations in the grid. The
time series files are named xxx_eta.ts1, xxx_u.ts1, and xxx_v.ts1.
Animation Output
Time-dependent output of the water surface elevation η(x,y,t) and horizontal
velocities uα(x,y,t) over a specified area and time period. The user specifies
(x2,y2), and grid skip interval for the output grid area, and the start time, end
time, and time-step for the output time period. The files are named xxx.eta
and xxx.uv for the surface elevation and velocities, respectively. The anima-
tion files could be large and should be used judiciously. The size of the sur-
face elevation output file in bytes can be calculated as 4 x (number of grid
points) x (number of time-steps). The velocity file is twice the size of the
surface elevation file.
Step 10.
After entering all the information, Pre-BOUSS2D creates a simulation parameter
file. The simulation parameter file is an ASCII file that can be edited using
37
Chapter 4 Setting Up and Running BOUSS-2D
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