IDD = Integer event identifier, such as a date or test number. The integer is
limited to nine digits.
U = Wind speed in meters/second. This wind speed is considered constant
over the entire grid. Winds that are blowing offshore (-x direction) are neglected
by the model, because the model only treats generation in a half plane. For wind
directions greater than 60 deg relative the x-axis, STWAVE underpredicts wave
generation (because of the half-plane model coverage). To model large ranges of
wind direction, multiple STWAVE grid orientations may be required.
UDIR = wind direction relative to the STWAVE coordinate system in
degrees. Wind direction is measured counterclockwise from the x-axis (same
convention used for wave direction, see Figure 3).
FM = Peak spectral frequency in Hz. If a spectrum is specified with no
energy (i.e., waves will be locally generated in the modeling domain), FM should
be set to the highest frequency specified in the model parameter file. This
parameter is no longer used in the STWAVE computations, but is calculated
from the input spectrum. A value for FM must be included in the input spectra
file to maintain backward compatibility with STWAVE version 2.0.
DADD = Water elevation correction (tide or storm surge) in meters, relative
to the bathymetry datum. Users should take special care to ensure a consistent
datum is used to specify the bathymetry and the water elevation correction. The
water elevation correction is constant over the entire grid. Positive values of
DADD increase water depth and negative values decrease water depths.
The header line is read in free format and is followed by the energy densities
in the units of meters squared/hertz/radian. The spectrum is read starting with the
lowest frequency and reading all the wave directions (from -85 deg to 85 deg),
then reading energy densities for all directions for the next lowest frequency, etc.
The total number of energy densities read equals the number of frequencies times
the number of directions.
Multiple wave model runs can be executed by inserting multiple spectra,
with identifying header lines, in the input file (the number of frequency and
direction bins and the frequencies are not repeated for each spectrum, but must
remain the same). The model will loop through the execution until it runs out of
input spectral information (model parameters and bathymetry will stay constant).
If wave-current interaction is specified (ICUR=1), the number of current fields in
the current input files must equal the number of input spectra. The default name
for the incident spectra file is spec.in. In SMS, the file is specified as
project.eng (.eng for energy density). A sample incident spectrum file is
given in Appendix C. The sample spectrum file has 25 frequencies and
35 directions. The spectral frequencies are from 0.01 to 0.25 Hz, incrementing
by 0.01 Hz. The event identifier is 200700 (12 March 1996 at 0200 GMT). The
wind speed is 15 m/sec, wind direction is 10 deg, and the tide/surge elevation is
-1.0 m relative to mean sea level (which corresponds to the mean sea level datum
used to develop the bathymetry file).
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Chapter 3 Input File Description
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