90 



wave ray 



'vl.6m 



_t ft- 



water surface gages 

 Figure 5.3: Layout of water surface array 



5.4 Theoretical Records 

 5.4.1 Single Wave Records 



The following results are from "measured" data generated by Fourier steady wave 

 theory (Sobey 1989). Fourier theory provides a near-exact solution for steady waves 

 that provides the complete kinematics. This approach provides a complete set of data 

 to compare with the results of the LFI method, without the complications introduced 

 by the inevitable errors of data collected in the field or the laboratory. Theoretical 

 records were used also because field or laboratory data that included a full set of 

 measured kinematics to compare with the results are not available. 



A triangular array of water surface measurements was used, as indicated in Fig. 

 5.3. The array is an equilateral triangle with the same dimensions as the DWG-1 

 pressure array (Howell 1992). Three measurements were chosen, as three is the min- 

 imum number required to provide directional information. Additional measurements 

 would provide overspecification, and can easily be accommodated in the formulation. 

 With actual field data, additional measurements are recommended, as increasing the 

 number of instruments would provide redundancy in the case of instrument failure, 

 as well as helping to accommodate measurement error. 



