201 



SENT METHOD 



10 20 30 40 



PRESENT METHOD 



o DATA 



PRESENT METHOD 



o DATA 



20 30 40 50 



FIGURE 13. Comparison of computed crossflow angle with Vermeulen ' s data. 



serves as an excellent case on which to apply our 

 method . 



Figure 19 shows a three-dimensional picture of 

 this ship model together with our nonorthogonal co- 

 ordinate system. We see from this figure that, as 

 a by-product of the mapping method discussed earlier, 

 the z = const, coordinate lines are concentrated 

 in the bow and corner regions where the curvature 

 is large. Figure 20 shows different cross-sections 

 (indicated by solid lines) and interpolated values 

 obtained by a cubic-spline method (indicated by 

 circles) from which the geometric parameters are 

 obtained. 



The inviscid velocity distribution for the model 

 is obtained by using the Douglas-Neiomann method 

 treating the model as a double ship model . Figure 

 21 shows the pressure distribution for the entire 

 ship and Figure 22 shows a detailed pressure distri- 

 bution for the bow region. We see from these figures 

 that the longitudinal pressure gradient near the keel 



FIGURE 14. Three-dimensional picture of double ellip- 

 ■tic ship model with the nonorthogonal coordinate system. 



FIGURE 15. Pressure distribution for the double- 

 elliptic ship. 



