User Defined Spectrum. Irregular Wave.

If a special wave energy spectrum should be used, the "USER" is specified under "SpectType". Following data have to be given:

• Hs and Tp
• "Random Seed" parameter, (instead of phase )
• Wave energy spectrum: USER
• Number of frequency components and the frequency range (T_low, T_high).
• Spectrum integration method (equal dOmega, Constant area, etc.
• Number of points in user defined S(w) vs w
• The nPoint w , S(w) points

The interpretation of the read-in spectrum is printed in the "out" file under "H y d r o d y n a m i c". Figure 1 shows the actual spectrum (cut/paste from the out file). Figure 2 presents the same spectrum but as a function of wave period. (=> See also Excel sheet , which is based on the Usfos out put ).

Usfos input files to the actual example are found in the following two files:

=> Usfos Control File
=> Model File

Figure 1: Plot of actual user defined wave spectrum. S(w) vs angular freq.

Figure 2: Plot of same wave spectrum. This time S(w) is plotted as a function of wave periods.

Figure 3 : Snapshot from the simulation using user defined S(w). Notice the "Applied Load" showing the wave load distribution.