ACCELERATION 
HORSEPOWER 
2 
4 
Theory of Stability of Laminar Flow 469 
RING THICKNESS 
eo= NO 
a= 1/16" 
= 1/2" 
v= 3/4" 
CONSECUTIVE 
DATA POINTS 
NON CONSECUTIVE 
BUT MAXIMUM 
POWER DATA 
POINTS 
<< 
8 
Fig. D3. Acceleration horsepower versus velocity 
measured, and this does not include the horsepower expended in overcoming drag. This 
value of power is in agreement with that which humans can exert for the same time period. 
The lack of acceleration data at low speeds is due to the previously mentioned camera mal- 
function. 
Figure D4 shows the results of the glide runs wherein the drag was calculated from the 
deceleration rate as the porpoise glided through underwater hoops. The data are plotted as 
drag area versus glide velocity, wherein the effects of virtual mass are included. This drag 
area is the drag divided by 1/2 pV”. The scatter of points for any one configuration is be- 
lieved due to movement of the porpoise while gliding. For numerous reasons, the maxima 
of these points are considered to approach the correct drag value of a motionless gliding 
porpoise. Figure D5 is a plot of this same data against ring thickness. The solid lines are 
the estimated drag area at various glide speeds. The dotted line is a curve faired through 
the maximum drag area data points and is believed to represent the minimum value of the 
experimental drag area of the porpoise. The wave drag has not been subtracted from this 
data, but it has been calculated to be small at the higher glide speeds. 
DRAG AREA, D' (FT®) 
TAIL MOVEMENT 
SEEN IN MAJORITY@ g2 
OF RUNS FOR 
D' <0.04 NO RING 
75-39 
<4 
RING THICKNESS 
4p 0Cbe 
none non 
ol 
~~ 
o 
THEORETICAL TURBULENT, 
NO RING 
THEORETICAL 40% LAMINAR, 
NO RING 
THEORETICAL LAMINAR, 
NO RING 
4m 18 
VELOCITY (FT/SEC) 
12) 16920) 24 728: 
Fig. D4. Drag area versus velocity 
