Table 8 



Critical HARBD Input Parameters and Ranges of Typical Values 



Parameter 



Where Specified 



Typical Values 



Short Waves 



Long Waves 



Bottom friction, P 

 Boundary reflection, K r 



Coastline reflection, K rc03St 

 Depth in infinite region. 



Number of terms in 

 Hankel function series 



Every element 



Every element on solid 

 boundary 



Single value 



Single value 



Single value 



0.0 

 0.0-1.0 



1.0 



0.0-0.1 

 1.0 



1.0 



Between avg. & 



nax. on semicircle 



8-100' 



8 



1 The number of terms needed increases as wave period decreases. 



where 



A amp = amplification factor 



a,a i = local and incident wave amplitudes 



H, //, = local and incident wave heights 



6 = phase relative to the incident wave 



Im{(f)} = imaginary part of <p 



Re{(f>} = real part of <p 



Amplification factors are easily interpreted. Phases are helpful in viewing wind 

 wave and swell propagation characteristics and in interpreting standing wave 

 patterns. In long wave applications, phases prove useful for determining relative 

 phase differences within the harbor, interpreting harbor oscillation patterns, and 

 identifying potentially troublesome nodal areas. 



Spectral adaptation 



HARBD computes harbor response to specified wave period and direction 

 combinations. However, the model is often used to approximate irregular wind 

 wave and swell behavior, as in physical model tests with irregular waves and all 

 field cases. More realistic numerical model simulations can be obtained by 

 linearly combining HARBD results from a range of regular wave frequencies and 

 directions in the irregular wave spectrum. With proper weighting, regular wave 

 results represent a desired spectral distribution of energy. 



Chapter 4 Numerical Model 



47 



