coordinate system and uses a numerical integration method that includes 

 the crossflow terms by an explicit method. The present calculation 

 scheme may improve on Larsson's results only in detail but not in a funda- 

 mental way. 



The surface coordinate grid on which the present calculations were 

 made is similar to but slightly coarser than the one shown in Figure 2. 

 The grid spacing is AO = 6 deg and As = 0.025 (As ^ A(J)) . The Chang 

 potential flow method was used to compute the values of the potential at 

 the center of rectangular elements in the (Q,<^) plane. These potential 

 flow rectangular elements (A9=10 deg, Act)=0.045) were much larger than the 

 grid elements of the boundary layer calculation so that the interpolation 

 technique with the cubic spline-on-spline described in the section on The 

 Ship Surface Coordinate System was used. 



Initial conditions for the quantities Q-.-., H, and t = tan 3 at station 



s = -0.5 (which very nearly coincides with one of the 6-coordinate curves 



21 

 on the surface of the hull) were obtained from Larsson's experimental 



results. These initial data are shown in Figure 8. Intermediate values of 



the data shown in Figure 8 were obtained by linear interpolation because 



it was felt that the sparsity and quality of the experimental data did not 



justify a more accurate interpolation. Figures 9 through 13 show the 



distributions of the streamline momentum thickness 6-, -■ , crossflow angle B, 



and skin friction coefficient C^ along the streamlines 1 through 8 of 



Figure 7. In each case, the results of the present calculation are 



21 

 compared to the corresponding results of Larsson's experiment and his 



calculation that includes the complete crossflow but not the modification 

 of the hull offsets by the values of the local displacement thickness. It 

 can be seen in Figures 9 through 13 that the present predictions seem to 

 correlate with the experimental data, on the average, about as well, or 

 possibly slightly better than, Larsson's computational results. In 

 particular, the present boundary layer predictions on streamline 5 extend 

 nearly to the stern of the model, in fairly good agreement with the experi- 

 mental data, whereas Larsson's results on this streamline seem to terminate 

 somewhat earlier, apparently because of some breakdown in his calculation 

 method. 



,42 



