Mori j Inui and Kajitani- 



(c) Amplitude function obtained from the measured free 

 waves by longitudinal cut method, 



(d) Amplitude function obtained from the measured free 

 waves by transverse cut method. 



As easily observed, the amplitude function (b) shows the 

 highest average level of free wave amplitude, particularly in the trans- 

 verse wave range. It appears that the difference between (b) and (c) 

 or (d) may be partially explained by the wave -breaking resistance. 



In Figures 25 and 26, Cw at the specific Froude number 

 Fn = 0. 2887, which is obtained from the longitudinal cut method (c), 

 is also presented. 



VI. SEARCH FOR THEORETICAL BASIS OF CORRECTION FUNCTION 

 « («) 



The practical usefulness as well as the experimental justi- 

 fication of the obtained correction function oc ( £ ) are clearly demons- 

 trated in the preceding sections. 



From a theoretical point of view, however, its hydrodyna- 

 mical mechanism still remains open for further investigations. 



From the standpoint of the boundary condition which is used 

 to obtain velocity potential in. Equation 2 , two possible causes for 

 the discrepancies between theoretical and wave-analyzed results can 

 be mentioned. Namely, (a) finite Froude number effect for the hull- 

 surface condition, (b) non-linear effect for the free-surface condi- 

 tion. 



For the time being, preliminary calculations of these two 

 higher order terms are carried out with respect to the amplitude func- 

 tions. 



VI. 1. Hull surface condi tion 



Throughout the present paper, the hull-generating source 

 m( £ ) is derived from the so-called double -model approximation m 

 which is correct only for limiting case Fn — ► or K L — *• °° . 



696 



