Wave Analysis Techniques to Achieve Bow-Wave Reduction 



o s*^-—2,5 



12.5 



Fig. 3 - Amplitude spectrum of 

 Inuid S-201 for >'(, =10 



The principal results of the three foregoing numerical tests on theoretical 

 wave systems can be summarized as follows. Both, the wave height and the 

 transverse slope, methods of longitudinal-cut analysis are essentially correct 

 and feasible. The accuracy of analysis is practically limited by two factors: 

 the finite transverse location y of the cut and the finite length of run in the neg- 

 ative X direction. The truncation errors are most prominent at the lower end 

 of the spectrum (about u = , that is, s = i) and are relatively less serious in 

 slope analysis than in height analysis (see Figs. 1 and 2). The latter, conducted 

 without truncation correction for any finite length of run however large, will al- 

 ways yield zero amplitudes at the point u = and will generally lead to large 

 errors of amplitude and phase in a significant portion of the spectrum (see Figs. 

 1 and 3), which may, however, sometimes cancel out in the integration and yield 

 a surprisingly reasonable value of wave resistance (see Fig. 1). The truncation 

 correction for height analysis as applied by the author seems to be most effec- 

 tive in the case of an isolated point disturbance and yields strikingly accurate 

 results (Fig. 1), while the improvement achieved in the case of a pair of point 



745 



