A viewgraph presentation describing aerodynamics at NASA Johnson Space Center is shown. The topics include: 1) Personal Background; 2) Aerodynamic Tools; 3) The Overset Computational Fluid Dynamics (CFD) Process; and 4) Recent Applicatoins

Vicker, Darby

NASA Technical Reports Server

Source of Acquisition 
NASA Johnson Space Center 
Aerodynamics at NASA JSC 
- 
EG - Aeroscience and Flight Mechanics Divisio 
EG3 - Applied Aeroscience & CFD Branch 
NASA Johnson Space Center 
Houston, Texas 
Presentation Outline 
Personal Background 
* Aerodynamic Tools 
The Overset Computational Fluid Dynamics 
(CFD) Process 
* Recent applications 
- X-38 
V-13 l r  Vehicle Scan 
AEDC Wind Tunnel Test 
STS- 107 Investigation 
0 Return to Flight 
- Shuttle 
2 
https://ntrs.nasa.gov/search.jsp?R=20060028488 2019-08-29T22:13:52+00:00Z
Personal Background 
Born and raised in Des Moines, LA 
A~ug 1997- Aug 1999,4 co-op tours 
- EP4, Propulsion and Fluid Systems 
- EG3, Applied Aeroscience and CFD 
- EM, Manufacturing - “The Shops” 
- EG5, Advanced Mission Design 
Ma-y 2000, graduated from Iowa State University 
with a Bachelors degree, Aerospace Engineering 
- o - - - ~ ~ ~ ~ ~ ~ t - ~ o o o - ~ ~ r e d - b y  -pJ-AS&!!G3 
I 
January 2001, started Masters degree at Rice University 
3 
Aerodynamic Tools 
X-38 Crew Return Vehicle 
Flight Test Wind Tunnel Test CFD 
4 
The Overset CFD Process 
What is CFD? - A “numerical wind tunnel” 
Geometry Database (CAD) 
- Mathematical Surface 
(Continuous) 
Surface Grids 
- Computational surface (disc 
- May arbitrarily overlap 
Volume Grids 
- Computational domain 
Flow Solqtion 
- Define flight conditions 
- Apply boundary conditions 
.ete) 
- Solve Navier-Stokes eq’ns 
Data Extraction 
- Calculate and validate 
the desired results 
V- 13 1R Analysis 
Background 
- “Unplanned maneuver” occurred during the first drop test of V13 1R 
- Post-flight analysis revealed an unmodeled aerodynamic force as the primary cause 
- A bent airframe was the prime suspected 
0 CFD used to characterize the bent airframe aero 
Photogrammetric scan of the vehicle was performed to obtain surface geometry 
- IGES surfaces created &om point cloud 2” above 
- 1.6 million points total in scan - average As = 0.4” (lower in high curvature areas) 
* CFD grids were created on the “as-built” IGES surfaces CAD 
6 
V- 13 1R Analysis 
Solutions obtained using OVERFLOW with the “as-built” grids 
Surface Cp delta between CAD and “as-built” 
X-38 Model G Wind Tunnel Test 
Arnold Engineering and Development Center 16’ 
transonic tunnel (AEDC 16T) in Tullahoma, TN 
- Pressure sensitive paint (PSP) data collection system 
Wind Tunnel Grids 
-__ --Nob:-every4%ointshown onX-38j-every-2ndpoint-- - 
shown on tnnnel and support structure 
TunnelModel G Grid System 
76 zones, 8.5 million points 
9 
Pressure Sensitive Paint 
Intensity based PSP system 
- Paint is excited by xenon lights 
- Light intensity emitted is dependant on the pressure 
Allows collection of high-resolution pressure distributions in WT 
PSP vs. CFD 
Mach 0.95, Abha 163 Beta Oo9 Flap 203 Rtcdder Oo 
- CFD Cp - PSP Cp 
11 
STS- 107 Investigation 
a Known: 
- Flight conditions at debris shedding 
- Debris came fiom left bipod ramp 
- Foam density approx 2.4 lbs/cu fi 
unknown: 
- Debris shape, size, mass 
- Initial conditions 
Desire: 
- Possible impact locations 
- Impact velocity 
- Impactangle 
\ 
left bi-pod ramp 
a Note: video evidence suggests impact velocities from 669 - 853 ft/sec: 
ambiguity due to distortions, lack of high-resolution / high-speed cameras 
12 
Cart3D 6- OF Results, Mach = 2.46 
1 .S 
Return-to-Flight 
0 Bipod ramps have been removed 
9 Shape change 3 Change in aerodynamics 
Old Configuration: 
Bipod Ramps 
New Configuration: 
Bare Spindle 
14 
Improvement of ET CFD Grid 
MAF CAD 
Grid detai 
region on 
/” t New CFD 
geometry 
OldCFD - 
geometry 
s ofboxed 
iext page 
Grid Comparison Detail 
16 
Flow Visualization - Mach 1.55 
Mach contours in Z = 564 inch cutting plane 
ETISRB ACp - Mach 1.55 
Bipod Redesign r l  Bipod Ramps Della 
0.00 
0.25 
- 0.25 
?- 
I 
0.00 
18 
Orbiter ACp - Mach 1 55 
Bipod Redesign Bipod Ramps rF-l Delia 
i 
19 
Inboard LO, Line ACp - Mach 1.55 
1.00 
0.75 
0.50 
0.25 
0.00 
-0.25  
1.00 
0.75 
0.50 
0.25 
0.00 
-0.25 
X,= 1050" 
X,= 1100 
X, = 1150 
20 
Wind Tunnel Test (IA-613) Comparisons - External Tank - Phi = 180" 
CFD conditions: MFA, = 1.25, a = -3.95', p =  O.OO", Reynolds # = 2.50 xl O%, IB elevon = 10.00", OB elevon = 5.00" 
WTT conditions: M, = 1.25, a = -3.95", 0 = O.OO", Reynolds # = 2.50 ~ 1 0 % ~  IB elevon = 10.00', OB elevon = 5.00" 
0" 
-0.5 
0 
0.5 
1 
1.5 
500 1000 1500 2000 2500 
c- 
21 
Wind Tunnel Test (IA-613) Comparisons - External Tank - Phi = 180" 
GFD conditions: M, = 2.50, a = 2.03', /3 = O.OO", Reynolds # = 2.50 x106/ft, IB elevon = 4.07, OB elevon = -4.39' 
WTT conditions: M, = 2.50, a = 2.03', J3 = O.OO", Reynolds #=  2.50 xlO%t, IB elevon = 4.07", OB elevon = -4.39' 
-0.5 1 
WTTCFD - 
1.5 1A-613BWTT 0 
I , . . . I , , . . l . . l ~ l . . . , ~  
500 1000 1500 2000 2500 
7
22 
CFD vs. IA-613B Wing Pressures 
-0.5 
Mach 2.50, Y = -250" 
- 
From WTT report: as measured elevons are: 
Left IB = 4.07"+0.09, Left OB = -4.39"+0. 11 
.___ .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
CFD conditions: M, = 2.50, a = 2.03', j3 = 0.00', Reynolds # = 2.50 x106/ft, $3 elevon E 4.00', OB elevon = -5.00' \ 
WTT conditions: M, = 2.50, a= 2.03", j3 I O.OO", Reynolds #=  2.5OxIO6/ft,!lB elevon =4.00', OB elevon = -5.00" 
I________________-____________________1 
n 
0" 
CFD vs. IA-613B Wing Pressures 
Mach 2.50, Y = -250" 
CFD run with as measured elevons 
CFD conditions: M, = 2.50, a = 2.03", j3 = O.OO", Reynolds # = 2.50 x106/R, IB elevon = 4.07, OB elevon = -4.39' 
WTT conditions: M, = 2.50, a = 2.03", j3 = O.OO', Reynolds # = 2 50 x106/ft, 16 elevon = 4.07", OB elevon = -4.39' 
-0.5 
0 
0.5 
1800 1900 2000 21 00 2200 2300 
X,, inches 
24 
CFD vs. IA-613B Left SRB Pressures 
0: 
0.5 
0" 
1 :  
1.5 
2 :  
: 
WTTCFD - : 
IA-613AWl-T @ 
IA-613AWl-T @ 
I , . . , I , . . . I . , , . I , , , r l  


Aerodynamics at NASA JSC

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