university of florida thesis or dissertation formatting template

Figure 6-3 and Figure 6-4 illustrate a sequence of images visualizing the flow computed on
the left wing (looking aft forward) for the sinusoidal rolling motion depicting Mach = 1
boundary and instantaneous vorticity magnitude iso-surfaces, respectively, with the pressure
coloring the aircraft surface. The roll angle is shown as a function of time in the lower right-hand
corner in each set of images. The left set of images, A) and B), display the 1Hz ±2° case results,
and the 8Hz ±0.5° case results are presented in C) and D) on the right. Looking at Figure 6-3, it
is difficult to see a difference in the Mach=1 iso-surface as the aircraft rolls. Upon animation, it
maintains a fairly constant size for the 1Hz ±2° case and appears to grow in size at the top of the
roll oscillation for the 8Hz ±0.5° case. The growth of this iso-surface for the 8Hz ±0.5° case
appears to lag behind the rolling motion of the aircraft, which is indicative of a phase
shift/hysteresis in the flow. This iso-surface also maintains a mostly constant position on the aft
portion of the wing, parallel to the TE. As the aircraft rolls left-wing-down, the Mach=1 iso-
surface begins to wrap around the wingtip at the LE to the bottom surface of the wing.
Figure 6-4 displays evidence of the vortices coming off of the strake in the cave-like
feature on the inboard portion of the wing for both cases. These vortices remain stationary
despite the motion of the aircraft when animated. Indication of the wing tip vortices
strengthening can be seen at the peak of the rolling cycle, and diminishing at the bottom of the
cycle, so that the strength of the vortices is offset asymmetrically on the wingtips. There is also a
delay in the strengthening of the tip vortex. It actually develops further as the wing begins to roll
down, and delays its shrinking until the wing has already begun its downward rolling motion.
This indicates a lag in the flow’s reaction to the rolling motion.
The instantaneous Cp measurements plotted against non-dimensional chord are plotted in
Figure 6-5 at 93% span and in Figure 6-6 at 88% span on the left wing for one developed cycle
72