It is to be noted that the experimental values of the crossflow angle 

 3 shown in Figures 9b, 10b, lib, 12b, and 13b all exhibit a change in sign 

 (hence crossflow reversal) between the stations s = 0.6 and s = 0.8. The 

 results of the boundary layer calculations shown in these figures consist- 

 ently miss this flow reversal. This indicates that the crossflow model may 

 need considerable improvement in order to reliably predict crossflow 

 reversal as the boundary layer approaches separation. However, the cross- 

 flow discrepancy at the stern of the SSPM Model 720 may also be due, in 

 large part, to the discrepancy between the potential flow pressure 

 distribution and the actual pressure distribution at the stern. The 

 experimental and computational results indicate that the boundary layer 

 is very thick at the stern of the model; hence, the pressure distribution 

 must be different from the potential flow values there. Note also that the 

 degree of accuracy in predicting the primary quantities of interest, the 

 boundary layer momentum thickness 0^ and skin friction coefficient C , is 

 considerably better than the prediction of the relatively small values of 

 the crossflow angle 3- 



On the basis of the comparisons with experimental boundary layer data 

 shown in Figures 9 through 13, the overall assessment of the present 

 boundary layer calculation method is that it can predict boundary layers on 

 relatively fine double ship models with fair accuracy to within a distance 

 of the stern of about 10 percent of the ship's length. In this area, the 

 boundary layer thickens very rapidly and approaches separation. Calcu- 

 lation of this near-separated boundary layer region must await further 

 developments of boundary layer theory. 



CONCLUDING REMARKS 

 This report presents a momentum integral method for computing three- 

 dimensional boundary layers for ships. Most of the technical details for 

 carrying out the computational problem of solving the momentum- integral 

 boundary layer equations are worked out here and have been implemented in a 

 set of computer programs. The basic method can be used to calculate 



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