university of florida thesis or dissertation formatting template

More documents

Recommendations

Info

wing-only case. The LE antenna vortex diminishes on the upper surface as the aircraft pitches down and grows as it pitches up. Additionally, much lower pressures across the wing-only case are present due to the increased strength and size of the Mach=1 iso-surface. A more substantial amount of separation can be seen aft of the shock transition on the upper surface for the wing- only case when examining the vorticity magnitude iso-surface in Figure 6-50 A) and C). This may be strong evidence of shock-induced separation. Additionally, this type of flow feature may play an important role in the LCO mechanism. Figure 6-51 shows the instantaneous Cp measurements plotted against non-dimensional chord taken at 89% span (BL159) for the one developed cycle of oscillation. Results for the wing-only case are shown in A) upper surface, and B) lower surface; and the aircraft comparison results are illustrated in C) upper surface and D) lower surface. Each numbered line (1-9) corresponds to the time-accurate oscillation cycle angle, in degrees, during the sinusoidal pitching cycle, indicated by the corresponding cycle angle color given in the legend in the upper right-hand corner. In Figure 6-51, it is seen that the Cp on both the upper and lower surface overlap for 0° and 360° cycle angles, but do not for 180°. One would expect, from a quasi-static perspective, that the coefficients would be the same for all of these cycle angles since they are at the same absolute AOA. Upon comparison of the wing-only case and the aircraft case, the same cycle angles pairing are evident, indicating the same inability of the flow-field to “keep up” with the motion of the structure, indicating a lag in the flow. The same suction loss feature is apparent for cycle angles 225°, 270°, and 315°, corresponding to the ascension, peak, and descension of the positive peak of the pitch oscillation in the 65-75% chord region on the upper surface. However, 102
on the upper surface, a much larger shock character in the 60-70% chord region is evident for the tip-launcher case. However, there is not much of a shift in the shock location. Upon examining Figure 6-51 and animating the Cp for all iterations on the upper surface, a rapid suction build-up with increasing AOA is revealed at the 50-70% chord location. As AOA decreases, there is a rapid loss of suction which progresses from the aft portion of the wing forward. The motion of this loss resembles that of a double hinged door slamming shut; the first near 70% chord and the second near 60% chord. This is an indication of the hysteresis behavior in the shock structure. The character of this motion is the same at this particular BL location for both cases, with the magnitudes of the overall Cp for the wing-only case larger for the upper surface and smaller for the lower surface. Looking at inboard BL locations in the shock separation region for the aircraft case and comparing the Cp at the same location for the wing- only, the same oscillatory behavior is not evident in the shock attributed to the separation. For the future purposes of this FSR work using prescribed motion, the lack of inboard shock separation should not be a problem when considering the flow at the outboard locations of the wing, such as BL159. However, when the time comes to examine LCO with a coupled, FSI code, modeling of the entire aircraft may be necessary to determine the importance of the presence of the strake vortex. Lissajous Analysis Figure 6-52 shows the set of Lissajous plots (-Cp vs. local displacement from the upper surface of the airfoil at various chord vs. span locations) for one cycle of rolling 8 Hz ±0.5° oscillation. A low pass filter is applied to the data at 100 Hz to filter out the noise due to turbulence effects. The top of the figure is the tip launcher, the bottom the wing root; and the left side is the LE and the right side the TE of the wing. The red circles indicate the starting point of the roll cycle, and the black arrows indicate the direction of rotation of the Lissajous. 103
Page 1 and 2:
TEMPORAL ANALYSIS OF TRANSONIC FLOW
Page 3 and 4:
To Dodjie 3
Page 5 and 6:
TABLE OF CONTENTS ACKNOWLEDGMENTS .
Page 7 and 8:
Summary ...........................
Page 9 and 10:
LIST OF FIGURES Figure page 2-1 F-1
Page 11 and 12:
6-9 Lissajous plots of upper surfac
Page 13 and 14:
6-45 2-D (left column) and 3-D (rig
Page 15 and 16:
incrementally since this capability
Page 17 and 18:
are not sufficient to provide an an
Page 19 and 20:
4. Contribute to the work of others
Page 21 and 22:
Classical aircraft flutter is chara
Page 23 and 24:
Popular methods for finding the sol
Page 25 and 26:
LCO amplitude but not the mechanism
Page 27 and 28:
speed for the particular configurat
Page 29 and 30:
Denegri 23 explains the flutter fli
Page 31 and 32:
Doublet-lattice Denegri 1, 7,12,13
Page 33 and 34:
Batina’s work and uses an F-16 ha
Page 35 and 36:
As a result of Denegri’s previous
Page 37 and 38:
Figure 2-1. F-16 store stations. Fi
Page 39 and 40:
Figure 2-5. Flutter flight test bui
Page 41 and 42:
Stokes (RANS) equations on hybrid u
Page 43 and 44:
CHAPTER 4 ANALYSIS TECHNIQUES Intro
Page 45 and 46:
time-localization cannot be determi
Page 47 and 48:
A B C D E Figure 4-3. Analysis of s
Page 49 and 50:
(CFD) analyses in order to capture
Page 51 and 52: the appropriate time step for the n
Page 53 and 54: Wing1, is the wing-only (no fuselag
Page 55 and 56: similar to DES but with modificatio
Page 57 and 58: Figure 5-1. Time step comparison of
Page 59 and 60: A B Figure 5-3. Flow results for 8
Page 61 and 62: A B Figure 5-5. Flow results for 8
Page 63 and 64: Figure 5-7. Turbulence model compar
Page 65 and 66: Figure 5-9. CFD vs. wind tunnel com
Page 67 and 68: Figure 5-11. CFD vs. wind tunnel co
Page 69 and 70: Figure 5-13. CFD vs. wind tunnel co
Page 71 and 72: server cluster comprised of 5,120 p
Page 73 and 74: of oscillation. The 88% span locati
Page 75 and 76: since it is proportional to lift, a
Page 77 and 78: of phase. Figure 6-10 B) and D) are
Page 79 and 80: The instantaneous Cp measurements p
Page 81 and 82: D Lissajous plots with time being t
Page 83 and 84: frequency of 8Hz. The wavelet plot
Page 85 and 86: vortex is observed travelling outbo
Page 87 and 88: near 70% chord and the second near
Page 89 and 90: expected from a lift curve slope. A
Page 91 and 92: shape of this Lissajous is nonlinea
Page 93 and 94: occurring at harmonics, and assumes
Page 95 and 96: the same direction of rotation on t
Page 97 and 98: the roll cycle, and the black arrow
Page 99 and 100: B) shows the fast Fourier transform
Page 101: is that shock separation aft of the
Page 105 and 106: Figure 6-1. F-16 wing planform with
Page 107 and 108: A C B Figure 6-4. DDES of F-16 in s
Page 109 and 110: Cp (Non-dimensional) Cp (Non-dimens
Page 111 and 112: -Cp (Non-dimensional) A -Cp (Non-di
Page 115 and 116: -Cp (Non-dimensional) A Time (sec)
Page 117 and 118: A B Figure 6-14. DDES-SARC of F-16
Page 121 and 122: Figure 6-18. Lissajous plots of upp
Page 123 and 124: -Cp (Non-dimensional) Frequency (Hz
Page 125 and 126: -Cp (Non-dimensional) A Frequency (
Page 127 and 128: A B Figure 6-24. DDES-SARC of F-16
Page 143 and 144: A B D Figure 6-40. DDES of F-16 in
Page 147 and 148: Figure 6-44. Lissajous plots of upp
Page 153 and 154:
A B Figure 6-50. DDES-SARC of F-16
Page 155 and 156:
Figure 6-52. Lissajous plots of upp
Page 157 and 158:
Impact on Future Design of Aircraft
Page 159 and 160:
The size of the Mach=1 iso-surface
Page 161 and 162:
these cases in order to identify th
Page 163 and 164:
15. Dawson, K. S., and Sussinham, J
Page 165 and 166:
41. Thomas, J. P., Dowell, E. H., a
Page 167 and 168:
67. Cunningham, A. M., Jr., and den
Page 169 and 170:
93. Parker, G. H., Maple, R. C., an
Page 171 and 172:
121. Travin, A. K., Shur, M. L., Sp
show all

university of florida thesis or dissertation formatting template

Create successful ePaper yourself

Delete template?

Save as template?