Deep-Diving Submarine Hydrodynamics 317 
Ref. 6. It will be noted that the critical Reynolds number reflecting an abrupt change in 
the flow regime takes place between the model- and full-scale range. These data were 
used to compute both the vertical velocities of ascent as well as the approximate 
periods of excitations that could cause oscillations of the Aluminaut during a rapid 
ascent. 
If the excitation periods computed in the preceding correspond to the natural period 
of oscillation of the submarine during any particular ascent, severe oscillations would 
Limit of experimental 
Hata with primes | Be scale range l|to7 ft/sec 
model 
0.8 
Cylinder Drag Strouhal 
Coefficient 
= 
aay 
o O06 
‘ 
°o 
Ss) 
mo 
= 
ra) 
a 
S) 
o 
‘p 
0.2 
48 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 656 
l0gig (Reynolds Number) 
Fig. 5. Effect of the Reynolds number on the vortex shedding frequency and the drag of cylinders 
646551 O—62 
22 
Num ber 
Strouhal 
