Analysis Used in Submerged Body Research 397 
in-phase and quadrature components of force are presented in Table 2. The derivation of 
these reduction equations is presented in Appendix B. 
Description of Facility 
The DTMB Planar-Motion-Mechanism System is a complete system for obtaining hydrody- 
namic coefficients from model tests. It embraces all mechanical, electrical, and electronic 
components necessary to carry out all functions from the delivery of the model to finalized 
processing of data preparatory to analysis. This includes preparation of the model for test- 
ing, conduct of static and oscillation tests, sensing and recording of test data, and process- 
ing data digitally in tabulated form. The main features of the system such as model support 
and positioning equipment, forced-motion mechanism, dynamometry, and Instrumentation 
Penthouse containing recording and control equipment are shown in Figs. 6 to 23. A descrip- 
tion of each of these components has been presented in great detail in Ref. 2. However, the 
roll-oscillation mechanism and new instrumentation system shown in Figures 15, 20, and 22 
were developed and placed into operation after the publication of Ref. 2 and have not been 
described heretofore. 
Roll-Oscillation System — Briefly, the roll-oscillation system produces an oscillation of 
the body about its longitudinal axes. Modifications and additions to the drive system and 
roll gage assembly, shown in Figs. 13 and 17, respectively, were required to incorporate 
this additional mode of motion. 
\emee 
TOWING 
OSCILLATOR MOTOR 
PHASE CHANGER 
fi) 
CARRIAGE | SUPPORT BRACKET 
1 XK VARIABLE-SPEED BELT DRIVE 
Cm 
Le.< PISTON 
WATERLINE 
APPROX. 
10' 
- — 
GAGE ASSEMBLY 
Fig. 6. Schematic arrangement of DTMB Planar Motion Mechanism with model attached 
646551 O—62——27 
