An of Propulsion for Mixed Flow Nozzle at Takeoff - NASA
Transcript of An of Propulsion for Mixed Flow Nozzle at Takeoff - NASA
NASA/CR-2001-211056
An
for Mixedof Propulsion
Flow Nozzle
at Takeoff
& Materials, Inc., Hampton, Virginia
2001
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NASA/CR-2001-211056
Computational Analyses of PropulsionAeroacoustics for Mixed Flow Nozzle
Pylon Installation at Takeoff
Steven J. Massey
Eagle Aeronautics, Inc., Hampton, Virginia
Kenrick A. Waithe
Analytical Services & Materials, Inc., Hampton, Virginia
National Aeronautics and
Space Administration
Langley Research Center
Hampton, Virginia 23681-2199
Prepared for Langley Research Centerunder Purchase Order L-13395
September 2001
Available from:
NASA Center for AeroSpace Information (CASI)
7121 Standard Drive
Hanover, MD 21076-1320
(301) 621-0390
National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161-2171
(703) 605-6000
Computational Analyses of Propulsion Aeroacoustics for
Mixed Flow Nozzle Pylon Installation at Takeoff
Steven J. Massey
Eagle Aeronautics, Inc.
Hampton, VA
Kenrick A. Waithe
Analytical Services and Materials, Inc.
Hampton, VA
June 21, 2001
1 Introduction
The objective of this task is to perform CFD analyses of a set of baseline and noise suppression
mixed flow nozzles with and without a pylon installation. This paper presents the full
CFD results from which the principal investigators of the study have recently published a
conference paper, Thomas et al. [1]. The five model configurations are as follows: a baseline
core/fan dual-stream nozzle with an external plug, a chevron mixer nozzle with a peak on the
symmetry plane with external plug, both of the above nozzles with an installed bifurcating
pylon and lastly a clocked chevron mixer nozzle such that a trough is aligned with the center
of the pylon. All grids cover 180 ° of the nozzle. The grids were constructed by GeoLab at
LaRC under a separate task. Since the cases were solved using two schemes, time marching
for the nozzle region and space marching for the far-field plume, the cell counts for the two
regions for each case are given separately in Table 1. In this study the flight takeoff (TKO)
flow conditions are solved on all models, see Table 2.
Table 1: Grid Size in Ceils
Time Marched Space Marched
Case Geometry Nozzle Plume Total
1 Round Nozzle 4,083,072 1,797,120 5,880,192
2 Round Nozzle w/Pylon 7,805,440 3,594,240 11,399,680
3 Chevron Nozzle 10,125,312 3,594,240 13.719,552
4 Chevron Tip under Pylon 12,620,096 3,594,240 16,214,336
5 Chevron Trough under Pylon 13,383,744 3,594,240 16,977,984
Table 2: Flow condition definitions.
Flow Condition Mach Pt[psi] Tt[R] FPR CPR Fan Tt[R] Core Tt[R]Takeoff (TKO) 0.28 14.7 530. 1.75 1.56 647. 1491.
2 Numerical Method
The fluid flow is simulated by solving the asymptotically steady, compressible, Reynolds-
averaged Navier-Stokes equations using an implicit, up-wind, flux-difference splitting finite
volume scheme and standard two equation k-c turbulence model with a linear stress repre-
sentation. All computations are performed using the multiblock, parallel, structured code
PAB3D [2]. Solutions are obtained using the flux difference splitting scheme of Roe, un-
coupled viscosity in the normal and circumferential directions, linear k-c turbulence model,
and a 2-factor scheme for the approximation of implicit terms. Grid sequencing is used to
accelerate convergence by solving 1/4 then 1/2 of the grid in each of the three computational
directions. The general solution procedure followed is to solve the region near the nozzle via
time marching, then solve the plume blocks via space marching, then finally run a compara-
tively small number of time marching iterations on the plume blocks and adjacent upstream
blocks in order to smooth any inflections at the time/space marching block boundary. Wall
clock run-time using four Compaq Alpha 500 MHz machines in parallel is (depending on grid
size) approximately 50 to 150 hours for time marching of the nozzle and nearby plume, 3-6
hours to space march the plume, and 4-8 hours to smooth out the solution by time marching
the plume. The final plume time marching is optional since the space marched solution is
already well converged. Due to the large size of these cases, they will scale very efficiently
to the larger clusters as they become available.
3 Results
In this study, the effects of geometry changes are sought on the precursors of noise, such as
turbulence and vorticity. It is hoped that any geometry change will not have a significant
effect on the performance of the nozzle. Grids and flooded solution contours are presented
in Figures 1-34 for the five cases identified in Table 1. Pylon flow topology is shown in
Figures 35 and 36. Model comparisons for axial variation of mass averaged quantities with
integration lower limits set to 100.5% of freestream Tt and 100.5% of fan Tt are plotted
in Figures 37 and 38 respectively. Mass averaged quantities are calculated at each axial
station by integrating over the area that contains flow above the chosen total temperature,
for example,
ka_ fA kpu dAfdpu dA (1)
with integration only performed over areas where
T__>1.005T_ or T_F_. (2)
Non-dimensional forms of total temperature and turbulence kinetic energy are shown in
Figures 39 and 40 respectively. The non-dimensional expressions are identical to those
published by Kenzakowski et al. [3] and are defined as follows:
Non-dimensional Average Total Temperature -
Average Turbulence Intensity -
fA Cpu dA
fA pu dA
fA _qqpU dA
fA pu dA
(3)
(4)
where
z
Tt -- TtFA N
TtCORE --TtFAN
with integration only performed over areas where
(5)
0.005_<¢ _<1. (6)
The integrations were implemented using a combination of Tecplot scripts and Fortran code
written by the authors specifically for this task. Lastly, axial variation of maximum total
temperature and specific turbulence kinetic energy are plotted in Figures 41 and 42 respec-
tively.
3.1 Case Round Nozzle
The round nozzle case is the baseline case from which the effects of the pylon and chevrons
will be evaluated. Although the geometry is axisymmetric, the case is still run as a 3-D half
plane with the same grid topology as the other cases, Figure 1. A typical maximum flow
vector residual history is shown in Figure 2, where the spikes highlight the change in grid
sequencing from 444 to 222 to 111. Because the round case is coarser than the other cases,
residual dropped only by a little more than three orders of magnitude. Finer cases typically
drop by more than four.
Contours of Mach number, Pt and Tt, shown in Figures 3-5, depict a clean symmetric
solution, despite the many block boundaries and the fact that the solution was space marched
beyond x - 13.7 core diameters. Note, in all cases length is in terms of the round nozzle
core diameter with the origin at the fan exit. For all Tt plots the contours are cutoff below
100.5% of freestream. Vertical cross-flow planes at x - 2, 4, 8, 16 core diameters, Figures 6
and 7, indicate a well developed solution with no asymmetry except for the log vorticity
magnitude. In _ is very sensitive to any solution fluctuations as well as grid quality.
3.2 Case Round Nozzle w/ Pylon
Figure 8 depicts the pylon and nozzle grid surfaces in black against the blue symmetry plane.
Close-up rotated views of the pylon/nozzle interface are shown in Figure 9. Symmetry plane
plots, Figures 10-12, show the strong vertical influence of the pylon (and lower bifurcator)
on the jet flow. Cross-flow plots, Figures 13-14, clarify the effect by showing the location
of the pylon in the flow and its azimuthal influence. It is clear from the pressure and total
temperature plots, that the pylon shields the top portion of the core flow from the high
pressure fan flow. This allows the core flow to follow the bottom contour of the pylon, which
due to its upward curvature imparts significant upward momentum. In comparison to the
baseline round case, a large increase of k can be seen in the x - 8 plane. As noise is a
function of turbulence, this peak is a likely source for noise.
3.3 Case 3_ Chevron Nozzle
Symmetry plane views show a well developed and vertically symmetric solution for the
chevron case, Figures 16-18. Because of the star-like cross-flow pattern caused by the
chevrons, contours on the symmetry plane can be misleading. An example of this is the
apparent source of Tt near the x - 6 station, which is simply the cross-flow lobe moving
closer to the symmetry plane. Cross-flow images, Figures 19-20 are all very symmetric and
indicate that future studies without a pylon may be carried out on 1/8 sector rather than the
present 1/2. The chevrons mix the flow very well while at the same time reducing average
and peak specific turbulence kinetic energy levels, Figures 37 and 42.
3.4 Case 4_ Chevron Tip under Pylon
In this case, the pylon was added to the chevron geometry, Figure 21. Close-up rotated views
of the pylon/chevron interface are shown in Figure 22. The introduction of the pylon to the
chevron jet flow produces the same effect as on the round jet, Figures 23-25. The new feature
is the top lobe of core flow is now drawn into the pylon, Figures 26-27, which produces a
strong attachment line coupled with a spiral separation on each side of the bottom the pylon,
Figure 35.
3.5 Case 5_ Chevron Trough under Pylon
The final case is constructed by rotating the chevrons such that the trough lies directly
under the center of the pylon, Figures 28-29. Moving the trough under the pylon has the
very beneficial effect of splitting a single cross-flow plume on the pylon, Figure 33, which
reduces the energy available to the pylon boundary layer and fan shear layer and thus results
in much lower specific turbulence kinetic energy levels, Figure 34. Separation is also reduced
and moved to the sharp outer edge of the pylon, Figure 36. A strong attachment line is
also observed in close alignment with the chevron edge on the bottom of the pylon. For
reference, the round nozzle with pylon case did not incur any flow separation on the pylon
and both chevron with pylon cases did not have any further flow topology features outside
the boundaries of the figures shown, Figures 35 and 36.
3.6 Axial Distributions
With the exception of turbulence kinetic energy and vorticity, mass averaged quantities of
the full jet using a temperature integration lower limit of 100.5% of Ttoo are largely diluted
by the inclusion of fan flow, Figure 37. To better isolate the mixing between the fan and
core flows, averages are taken using a temperature integration lower limit of 100.5% of TtFAN,
Figure 38. From the latter set of averages, and the non-dimensional averages, Figures 39
and 40, it is clear that the core chevrons significantly enhance mixing while the pylon itself
providesaslight increasein mixing for round and chevroncases.In terms of peak turbulencekinetic energy,Figure 42, the clockedchevronis muchlower than the other pylon cases,whileslightly higher than the no-pylon cases.
4 Concluding Remarks
In general the cases ran very well. Techniques have been developed to extract quantitative
characterizations of the jet flows. Further study is required to refine expressions which are
indicative of noise and mate these with rigorous noise prediction models. It is concluded
that the clocked chevron with pylon case achieves the most optimal levels of average and
peak turbulence kinetic energy and vorticity and therefore is expected to be the quietest of
the five configurations tested.
The authors wish to gratefully acknowledge the Configuration Aerodynamics Branch of
LaRC for the use of their Alpha clusters to complete the cases in this study. All data and
post processing files and scripts are included in the deliverables on CD-ROM.
References
[1] Thomas, R. H., Kinzie, K. W., and Pao, S. P., "Computational Analysis of a Pylon-
Chevron Core Nozzle Interaction," AIAA Paper 2001-2185, 2001.
[2] Abdol-Hamid, K. S., "Development of Three-Dimensional Code for the Analysis of Jet
Mixing Problem," NASA CR 4200, 1988.
[3] Kenzakowski, D. C., Shipman, J., and Dash, S. M., "Turbulence Model Study of Lab-
oratory Jets with Mixing Enhancements for Noise Reduction," AIAA Paper 2000-0219,2000.
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from the fan exit.
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starting from the fan exit.
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fan exit.
16
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starting from the fan exit.
17
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Figure 22: Case 4, Chevron Tip under Pylon: pylon grid interface views, with symmetry
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II
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SCO
X=4D o
989985
;:',_X2_E7
)43 Ou
")4_0
X=4D o
I 0 05 oo ,3,5 10 15
Z/D c
X=4D o
Z/D c
7_2
7E4
6,964
60s5_5
5_7_j
IIST_SS_
SCO
X=8D c
)S9
)S598)
97'3371366
)62
9.%
_43
_S9 _-
_25
X=8D c
I.s o o_ ,., ,z,.b /o 1_
Z/D c
X=8D c
15
Z/D c
X= 16D c X=16D c X=16D c
)S9
)S598)
97'3371
366)62
9.%
_43
_S9 _-
_25
I.s o o_ ,., ,z,.b /o 1_
Z/D c
Figure 26: Case 4, Chevron Tip under Pylon: Mach number, Total Pressure[kPa] and Total
Temperature [K] contours at stream-wise stations x = 2, 4, 8, 16 core diameters, starting
from the fan exit.
20
k [kJ/kg]X=2D o
[I/s]X=2D o
2_ 0 I 5 I 0 05 00 c 5 c 5 2 c
Z/D c
25 2,, 5 10 ,, oo 05 IC 15 2,, 25
7JD c
X=4D o X=4D o
2_ 0 I 5 I 0 05 00 c 5 c 5 2 c
Z/D c
25 2,, 5 I0 ,, oo o5 IC 15 2,, 25
7JD c
X=8D c X=8D c
292O /L /0 Ob O0 C.b C .b 2.6
Z/De
2b 2.'3' .b /0 0.s O00.L 1.6 /L 2.'3' 2.b
Z/D c
X= 16D c X= 16D c
£b 2.'3' .b /0 0.s O00.L 1.6 /L 2.'3' 2.b
Z/D c
Figure 27: Case 4, Chevron Tip under Pylon: Specific Turbulence Kinetic Energy [kJ/kg] and
Log Vorticity Magnitude [1/s] contours at stream-wise stations z = 2, 4, 8, 16 core diameters,
starting from the fan exit.
21
Figure 28: Case5, ChevronTrough under Pylon: grid close-upview, with symmetry planeshownin blue.
Figure 29: Case5, ChevronTrough under Pylon: pylon grid interfaceviews,with symmetryplaneshownin blue.
22
5.0 10.0 15.0 20.0 25.0 30.0
XtD c
4-19_ 377
ss5i_i_i_i_i_i_i_i_i_i_i_i292
250
_ 2076522
80
Figure 30: Case 5, Chevron Trough under PylonAxial Velocity Ira/s] contours.
68
595142342517O800
5.0
rj
0.0
-5,05. 0
819::::::::::::::::::::::754
6a9iiiiiiiiii@i_i624
5604-95
4-303653OO0.0 5.0 10.0 15.0 20.0 25.0 30.0
XID c
Figure 32' Case 5, Chevron Trough under Pylon: Total Temperature [K] contours.
23
MX=2D c
)S9)S5
98)97'S
371)66
)62
9.%_48
ao
_25
[kPa]X=2D o
I 0 05 oo ,,5 10 15
Z/D c
1.5
I .C
,, 5
,, C
,;,.5
I .C
[iqX=2D o
1"51 0 05 8,8, ,,5 I0 15
Z/D c
7_2
7_4
6,964
60s5E5
5_7
II
ST_SS_
SCO
X=4D o
989985
;:',_X2
)43 Ou
")4_0
X=4D o
I 0 05 oo ,3,5 10 15
Z/D c
X=4D o
Z/D c
7_2
7_4
6,964
60s5E5
5_7_j
IIST_SS_
SCO
X=8D c
)S9
)S598)
97'3371366
)62
9.%
_43
_S9 _-
_25
X=BD c
I.s o o_ ,., ,z,.b /o 1_
Z/D c
X=BD c
15
Z/D c
X= 16D c X=16D c X=16D c
)S9
)S598)
97'3371
366)62
9.%
_43
_S9 _-
_25
I.s o o_ ,., ,z,.b /o 1_
Z/D c
Figure 33' Case 5, Chevron Trough under Pylon: Mach number, Total Pressure[kPa] and To-
tal Temperature [K] contours at stream-wise stations x = 2, 4, 8, 16 core diameters, starting
from the fan exit.
24
k [kJ/kg]X=2D o
[I/s]X=2D o
2_ 0 I 5 I 0 05 00 c 5 c 5 2 c
Z/D c
25 2,, 5 10 ,, oo 05 IC 15 2,, 25
7JD c
X=4D o X=4D o
2_ 0 I 5 I 0 05 00 c 5 c 5 2 c
Z/D c
25 2,, 5 I0 ,, oo o5 IC 15 2,, 25
7JD c
X=8D c X=8D c
292O /L /0 Ob O0 C.b C .b 2.6
Z/De
2b 2.'3' .b /0 0.s O00.L 1.6 /L 2.'3' 2.b
Z/D c
X= 16D c X= 16D c
£b 2.'3' .b /0 0.s O00.L 1.6 /L 2.'3' 2.b
Z/D c
Figure 34: Case 5, Chevron Trough under Pylon: Specific Turbulence Kinetic Energy [kJ/kg]
and Log Vorticity Magnitude [l/s] contours at stream-wise stations z = 2, 4, 8, 16 core di-
ameters, starting from the fan exit.
25
Figure 35: Case 4, Chevron Tip under Pylon: Pylon surface streamlines. Core nozzle shownin red.
Figure 36: Case 5, Chevron Trough under Pylon: Pylon surface streamlines. Core nozzleshown in red.
26
0.20
0.18
0.16
0.14
E0.12¢=.¢ 0.10
0.08
0.06
0.04
0.02
0.00
J .... I .... I .... I .... I .... I ....
_.._._.._i R°und w/Pylo n _z/_
..... _ ..... Chevron //._/_.:_'# /
....... 4- ....... Oh ..... / Pylon _/{_'/
Clocked Chevron w/Pylon ,_,_._,
/f
_e
• .... i .... i ..........5 10 '1;' '2'0'X/D c
o
7.0.1 .... i .... i .... i .... i .... i ....
I ...... ! ..... Round
........_........Round w/Pylon6. 0
.... :3 .... Chevron , _
....... 4- ........ Chewon w/Pylon _,/&_"
5.0 + Clocked Chevron w/Pylon /
4.0
3.0
2.0
1.0,
5 '1'0' 'l'a" '2'0'X/D c
3OO
_' 280
260o.
Eo 240O
"_ 220
:= 200
180==_ 160
_ 140
120
' ' ' i .... i .... i .... i .... i ....
_4_ ----I---Round
- _ Round w/Pylon
'_'_f_ :--:-:-4.:--:-:-oOheeVrro°nnw/Pylon
_&, + Clocked Chevron w/Pylon
.... i .... i .... i .... i .... i ....
5 10 15 20 25 30
X/D c
45O
440:
_, 430420
E 410
I_ 400
¢= 390O
I- 380
370
36O
350
=E 340
330
320
310
4 .... I .... I .... I .... I .... I ....
----!--- Round
_" Round w/Pylon
_; - - - _ - - - Chevron
_. ....... -4 ....... Chevron w/Pylon
"_,_ _ Clocked Chevron w/Pylon
.... 5 .... 110 .... 115 .... 210 .... 215 .... 30
X/D c
,,i
==
1 12 _ ........ /_ _-I _ _: ............
11-1- ,j
o.9- .¢._--_',_
0.7 -- ." _x,o.o_°si/ .0.4 --1-- Round _t_
0.3 _"_ ;, Round w/Pylon
oI2_/ _- -. _h'ev_on w/Pylon
O.1 _ _ ClockedChevronw/Pylon
0 0 5 10 15 20 2=* I I I I 15 30
X/D c
11000
_.0000
_9000
_8000
.__7000o
6000O
> 5000
4000
_3000
2000
1000
.... i .... i .... i .... i .... i ....
...... 1 ..... Round
....... # ........ Round w/Pylon
..... 3 ...... Chevron
....... 4 ........ Chevron w/Pylon
Clocked Chevron w/Pylon
5 10 15 20 25 30
X/D c
Figure 37: Full Jet: Axial distribution of Jet Area [m2], Jet Mass, Mass Averaged Axial
Velocity [m/s], Total Temperature [K], Specific Turbulence Kinetic Energy [kJ/kg] and Log
Vorticity Magnitude [l/s].
27
0.014
0.012
0.010
E0.008
'_ 0.006 J
0.004
0.002
0.000 0
,,, j_
,.,
_J/,
//! t
/l"
¢,
--I--- Round
....... :?........ Round w/Pylon
...... _i ..... Chevron
....... 4- ....... Chevron w/Pylon
Clocked Chevron w� Pylon
5 10 15 20 25 30
X/D c
0.00
Round
Round w/Pylon
..... ?, .... Chevron
........ 4 ........ Chevron w/Pylon
Clocked Chevron w/Pylon
5 10 15 20 25
X/D c
30
o.
EOo
"6
===E
4OO
35O
3OO
25O
2OO
I , , , , I , , , , I , , , , I , , , , I , , , , I , , , ,
--1-- Round "_.
....... 4........ Chevron w/Pylon
Clocked Chevron w/Pylon
0.... ; .... 1'0.... 1;.... 2'0.... 2; _0X/D c
85O
800 I
750o.
E 700I--_ 650O
I- 600
> 55o
==m 500=E
450
400
35O
I , , , , I , , , , I , , , , I , , , , I , , , , I , , ,
----_--- Round- ;' Round w/Pylon
[ ::-:-:-4.:--:-:-oOheewWo°n n w/Pylon
_ + Clocked Chevron w/Pylon
• \'1
_, "X \
", \:\?,
i .... i ,
0 5 10 15 20 25
X/D c
30
_2.0
1.5,v,
_1.0
=E 0.5
!
/
...... I ...... Round
....... :_"........ Round w/Pylon
i .... !_ ..... Chevron
+ Chevron w/Pylon
i. + Clocked Chevron w/Pylor
0% ..... _.... 1'0.... 1'5.... 2'0.... 2'5.... 30X/D c
20000 1
...... 1 ...... Round
_17500 ........_........ Roundw/Pylon_'-- .... '_ .... Chevron
_15000 ---4--- Chevronw/PylonClocked Chevron w/Pylon=E
_,_,__12500 "',._o
o 10000
7500
m 5000
2500
00 5 10 15 20 25 30
×/D c
Figure 38: Core Jet: Axial distribution of Jet Area [m2], Jet Mass, Mass Averaged Axial
Velocity [m/s], Total Temperature [K], Specific Turbulence Kinetic Energy [kJ/kg] and Log
Vorticity Magnitude [1/s].
28
11
0.9
0.8
0.7E"o0.6
E 0.5
_,_0.4
0.3
0.2
0.1
0
J''' ' I'''' I'''' I''' ' I''' ' I ' ' '
--_ - -1- Round
..........._ ............ Round w/Pylon...... 3 ...... Chevron
----4---- Chevron w/Pylon
- '!_ _ Clocked Chevron w/ Pylon
i i i
0 5 10 X15/Dc 20 25- 30
Figure 39: Mass averaged non-dimensional Total Temperature decay
0.200
0.1 75
0.150
E"D 0.125
E"D 0.100O"
_0.075
0.050
J
0.0251
0.000
'''' I'''' I'''' I''' ' I''' ' I ' ' ' '
/ 3
,/Z / / -- -1- Round
._/ / ...........2 ............ Round w/Pylon
:_ j 4 ...... 3 ....... Chevron,, --4--- Chevron w/Pylon
- _ _ Clocked Chevron w/Pylon
l..h , , , I , , , , I , , , , I , , , , I , , , , I , , , ,
o 3o
Figure 40: Mass averaged non-dimensional Turbulence Intensity decay
29
8OO
,--, 7005.Eo
--_ 600
OI'-x
500=E
4OO
\\ i', _
.........1 ........ Round \\'._,_"Round w/Pylon--"-'_
........(,".,........ Chevron" _'_._. \
Chevron w/Pylon "_'_.
, ,0 5 10 15 20 25 30
X/D c
Figure 41: Axial distribution of maximum Total Temperature [K]
11
10
9
ui 7,_ 6
5_ 4
_ 3
2
1
'' ' I''' ' I''' ' I''' ' I''' ' I''' '_-
, -1- - Round
Round w/Pylon....... _._....... Chevron
Chevron w/PylonClocked Chevron w/ Pylon -
.................... -
,,,, I,,, , I,,, , I,,,, I,,, , I , , , ,
0 5 10 15 20 25 30X/D c
Figure 42: Axial distribution of maximum Specific Turbulence Kinetic Energy [kJ/kg]
30
REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing datasources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any otheraspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations andReports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188),Washington, DC 20503.
1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
September 2001 Contractor Report
4. TITLE AND SUBTITLE 5. FUNDING NUMBERS
Computational Analyses of Propulsion Aeroacoustics for Mixed Flow
Nozzle Pylon Installation at Takeoff PO L-13395
6.AUTHOR(S)Steven J. Massey and Kenrick A. Waithe
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
Eagle Aeronautics, IncHampton, VAAnalytical Services and Materials, Inc.
Hampton, VA
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
National Aeronautics and Space AdministrationLangley Research Center
Hampton, VA 23681-2199
WU 706-32-41-03
8. PERFORMING ORGANIZATION
REPORT NUMBER
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
NASA/CR-2001-211056
11. SUPPLEMENTARY NOTES
Langley Technical Monitor: S. Paul Pao
12a. DISTRI BUTION/AVAILABILITY STATEMENT
Unclassified -Unlimited
Subject Category 02 Distribution: NonstandardAvailability: NASA CASI (301) 621-0390
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words)
A CFD analyses is presented for a set of baseline and noise suppression mixed flow nozzles with and without a
pylon installation. The five model configurations are as follows; a baselinecore/fan dual-stream nozzle with anexternal plug, a chevron mixer nozzle with a peak on the symmetry plane with external plug, both of the above
nozzles with an installed bifurcatingpylon and lastly a clocked chevron mixer nozzle such that a trough isaligned with the center of the pylon. The fluid flow is simulated by solving the asymptotically steady,
compressible, Reynolds-averaged Navier-Stokes equations using an implicit, up-wind, flux-difference splittingfinite volume scheme and standard two equation k-epsilon turbulence model with a linear stress representation.
All computations are performed using the multiblock, parallel, structuredcode PAB3D. Results indicate that theclocked chevron with pylon case achieves the most optimal levels of average and peak turbulence kinetic
energy and vorticity and therefore is expected to be the quietest of the five configurations tested. Further study isrequired to refine expressions which are indicative of noise and mate these with rigorous noise predictionmodels.
14. SUBJECT TERMS
PAB3D; CFD; Aeroacoustics; Pylon; Chevron; PAA; QAT
17. SECURITY CLASSIFICATIONOF REPORT
Unclassified
18. SECURITY CLASSIFICATIONOF THIS PAGE
Unclassified
19. SECURITY CLASSIFICATIONOF ABSTRACT
Unclassified
15. NUMBER OF PAGES
3516. PRICE CODE
A03
20. LIMITATIONOF ABSTRACT
UE
NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Std. Z-39-18298-102