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oscillation is examined at the same flow conditions (Mach=0.9, 5,000 feet, initial AOA=1.34°)
for direct comparison to the clean-wing Grid0 case.
Figure 6-13 and Figure 6-14 illustrate a sequence of images visualizing the flow computed
on the left wing for the sinusoidal rolling motion depicting instantaneous Mach = 1 boundary and
vorticity magnitude iso-surfaces, respectively, colored by pressure. The roll angle is shown as a
function of time in the lower right-hand corner in each set of images. The right set of images, A)
and B), display the tip-launcher Grid4 case results, and the clean-wing Grid0 comparisons are
presented in C) and D). The addition of the tip launcher and LE antennae significantly influence
the nature of the Mach=1 and vorticity magnitude iso-surfaces where expected for this case, such
as the cave created by the LE antennae and the wrinkle due to the tip launcher.
Looking at Figure 6-13 A) and B), it is difficult to see a difference in the Mach=1 iso-
surface as the aircraft rolls. Upon animation, the growth of this iso-surface 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. Upon animation of the tip-launcher case, it
is revealed that as the aircraft pitches nose-down, the Mach=1 iso-surface completely wraps
around the wingtip at the LE to the bottom surface of the wing and surrounds the LE antennae. It
should be noted that the shock on the front of the engine is due to faults with the engine model
resulting in a “throttle chop” flow feature that will be resolved in future simulations. Vortices are
also observed in Figure 6-14 rotating along the tip launcher, corresponding to the rolling up and
down of the wing.
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