PITCH 

 .200 \- SECTION 2 (AFT) 



Fn = .20 



CD 



.100 - 



+ 100 - 



+ 200 - 



+300 - 



Distribution of Hydrodynamic Forces on a Shipmodel 



1 1 1 1 1 1 1 1 1 1 1 1 1 I 1 



QUADRATURE COMPONENT 



-1 1 1 1 1 1 1 »* I 1 1 1 1 1 1 1 — 



12 3 4 5 6 7 ^\ 9 10 11 12 13 U 15 



00— ►CIRCULAR FREQUENCY 

 rod/sec 



IN PHASE COMPONENT 



e = 



2 r 



a L 

 • r = 1 cm 

 a r = 2 cm 

 A r = 3 cm 



J I I i_ 



50 



*n 

 40 O 



c 



Ul 



30 •« 



Ll. 



20 



10 -I 

 



CD 



Fig. 4 - Components of force on section 2, pitching motion 



PRESENTATION OF THE RESULTS 



Whole Model 



It is assumed that the force F and the moment M acting on a forced heaving 

 or pitching shipmodel can be described by the following equations: 



Heave 



(a + pv) Zq + bz^ + cz^ = F^ sin (wt + a) 

 Dz„ + Ez„ + Gz„ = -M, sin (a;t+ /3) 



O O O Z \ /- / 



Pitch 



(A+kyyPv) & + B0 + C6 = Mg sin (cot + y) 

 d'e + e'd + gd = -F^ sin (cot + S) 



For a given heaving motion z^ = z^ sin cot, it follows that: 



-M sin /5 



F^ sin a 



E ^ 



cZg - F^ COS a gz + M cos /3 



- pv D = 



(1) 



(2) 



(3) 



221-249 O - 66 - 16 



225 



