ship Maneuvering in Deep and Confined Waters 



Note that the factor 2 has been retained, which should not have been 

 the case if v and |v| had been treated as independent variables; 

 this, however, would only have been a formal artifice with no 

 physical significance. 



In straight -line oblique motion the non-dimensional lateral 

 force is Y" (u", v", v"^ |v"|/v"), or, in accepted writing 



Y"(u",v") = Y;', u"v" +iY" |v"|v 



Iviv 



(6.6) 



where 2^,". = - Cq* I- T/ZV. It is obvious that here two terms 

 are added, which each one corresponds to a certain flow field. In 

 the discussion of the "linear" term it was pointed out that the ideal 

 flow picture would remain valid over the bow portion of the hull, 

 and in view of the finite time required for the development of the 

 viscous cross-flow these conditions may still be true at larger 

 angles of drift, (Cf. non-linear theories for the lift of zero -aspect- 

 ratio wings, ) 



^v2lT 



Fig. 15. Calculated and measured lateral forces on a cargo liner 

 model in oblique towing. 



847 



