Sec. 52.6 



FLOW PATTERNS AROUND SHIPS 



247 



speed-length or Taylor quotient T„ or the Froude 

 number F„ . It is known that, in general, when 

 the crest of a transverse wave of the Velox system 

 generated by the bow coincides with the first 

 wave crest of the stern Velox system, there is a 

 drop in total resistance. When a trough of the 

 bow system coincides with a crest at the stern, 

 there is a rise in resistance. When these effects 

 are plotted on a base of speed-length quotient 

 T, or F„ , the humps and hollows in the curve of 

 total (or wavemaking) resistance are found to 



fall in the positions indicated along the lower 

 edge of Fig. 66.A. 



It is also known, for ships of normal form, 

 that certain T, values correspond to ship lengths 

 that are multiples of the transverse-wave lengths 

 in whole numbers. Roughly: 



(1) For T, = 0.63, the ship is 4 wave lengths long 



(2) For r, = 0.72 to 0.73, the ship is 3 wave 

 lengths long 



(3) For r, = 0.88, the ship is 2 wave lengths long 



AP 19 16 17 16 15 14 13 la II 10 9 8 7 6 5 4 3 2 I FP 



Fig. 52. J Wave Profiles for TMB Series 57, Model 4202W-1, at Various Speeds 



