outermost rows of the model grid are specified initially from wave input data, 

 allowing computation of values on all other rows. 

 Model use 



20. Wave climate data were provided at the boundary of the computational 

 grid (Figure 2) by WESWIS. With the wave height, period, and direction of 

 propagation prescribed at the ocean boundary, the wave propagation model 

 determines wave heights, directions of propagation, and wave numbers at all 

 4,158 grid points in the computational grid. If the wave height at any grid 

 cell is greater than 0.78 of the local water depth, the model assumes that the 

 wave is breaking and, based upon nonsaturated wave-breaking theory, sets the 

 breaking wave height equal to 0.78 of the water depth. 



21. Figures 3, 4, and 5 demonstrate the application of the wave model to 

 Oregon Inlet (existing conditions). Each of these figures corresponds to a 

 particular wave condition in deep water and shows the region near the inlet 

 channel and shoals. The wave height and the period in deep water are the same 

 for the three cases and are equal to 2.175 ft and 6.0 sec, respectively. The 

 wave direction in deep water is given by 9 = 45, 0, and -45 deg, respec- 

 tively, for the three cases where 6 is the angle the wave propagation 

 direction makes with the normal to the shoreline. A uniform grid with Ax = 

 Ay = 240 ft was used for these runs. In each figure, the depth contours are 

 represented by dashed lines, the wave height contours by solid lines, and the 

 wave directions by vectors. Figure 3 represents waves propagating approxi- 

 mately in the direction of the channel. The waves are refracted onto the 

 shoals, on either side of the channel, where they eventually break. As a 

 result, very little wave energy is propagated up the channel. Figure 4 shows 

 the inlet response for waves incident normal to the shoreline. Again the 

 waves refract onto both shoals and break. There is a decrease in wave height 

 just outside the shoals. Figure 5 illustrates a condition where the waves are 

 obliquely incident, in a direction approximately normal to the channel. Waves 

 converge on the near shoal, but note how they refract around the far shoal and 

 eventually converge with reformed waves propagating across the channel. The 

 computational requirements for the wave model were very modest. For the 

 4,158-cell variable grid, the cost per run was under $4.00. 



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