71^ - 



non-smoothed seven-coefficient Fourier series directional 

 distribution, presented in Figure IV-10, demonstrates a wide peak of 

 80 degree half-power bandwidth. The distribution suggests 

 omnidirectional wave power, but with a maximum at the mean of the two 

 simulated directions, 80 and 195 degrees. 



The identical case was re-simulated with the 80-degree wave 

 retaining its three foot height and the 195-degree wave assuming a 

 four foot height. The directional distribution, shown in Figure 

 IV-11, is asymmetrical with peak energy at the weighted average value 

 of the two wave directions. 



Inclusion of higher order terms in the partial Fourier series 

 representation of direction should increase the accuracy of the 

 series representation. Figure IV-12 illustrates the heightened 

 directional resolution of a simulated wave train at a principal 

 frequency using the first seven directional Fourier coefficients, 

 (N=3) , compared to the first five, (N=2) . The non-smoothed 

 half-power bandwidth for seven coefficients is 66 compared to 76.3 

 for five. 



In the simple simulation analysis, the software appears to be 

 non-sensitive to wave direction — at least for the presence of only 

 one wave train. Four waves of equal energy and frequency, but 

 different direction, were each simulated individually over the DPG. 

 The directional distribution for each was overlaid upon one another 



