Laminar-to-Turbulent Transition in Hypersonic BL with Spanwise Inhomogeneity Roger Kimmel Principal Engineer Aerospace Systems Directorate Air Force Research Laboratory 16 July 2015 Distribution A: Approved for public release, distribution is unlimited. 24 June 2015, 88ABW-2015-3223
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Laminar-to-Turbulent Transition in
Hypersonic BL with Spanwise
Inhomogeneity
Roger Kimmel
Principal Engineer
Aerospace Systems Directorate
Air Force Research Laboratory
16 July 2015
Distribution A: Approved for public release, distribution is unlimited. 24 June 2015, 88ABW-2015-3223
2
Overview
• Introduction
– Focus on BLT with significant spanwise nonuniformity
– Examine limits of applicability for PSE
• HIFiRE-5
– IR and Kulite measurements in Purdue
• Cone at AoA
– Stability calculations
– Re-examination of Stetson high-Reynolds Mach 6 data
• HIFiRE-1, 5a analysis
• Test capability development
– Ludwieg tube
– FLDI
– Krypton PLIF
16 October 2015
3
Push to Complex Configurations
16 October 2015
HIFiRE-5
Li 2012
Kimmel 1995
DARPA / AF Falcon HTV-2
Advanced Hypersonic
Weapon
4
Flows With Strong Spanwise
Nonuniformity
16 October 2015
HIFiRE-5 Gosse
(2009) Elliptic Cone
Huntley (2000)
HIFiRE-5
Paredes (2014)
What are limits of applicability
for PSE in complex flows?
When do non-modal
instabilities become
important?
5
Approach / Benefits
• Generate flowfields with spanwise nonuniformity
• Measure stability characteristics and compare to
PSE, search for regions where PSE may be
inadequate
• Benefits – increased confidence with PSE, improved
vehicle design
16 October 2015
Borg – HIFiRE-5
Crossflow
development
Jewell – Cone at AoA
Instability growth with
varying spanwise
nonuniformity
Tufts – PSE
Modal instabilities
in 3D flows
6
Last Year’s Results
• HIFiRE-5
– Measured fluctuating surface pressures in TAMU ACE wind tunnel
– Mach 6 results similar to Purdue noisy, but lower amplitude
– Strong effect of Mach number and tunnel conditions on observed instabilities
• HIFiRE-1 high AoA transition
– 2nd mode observed on cone at AoA in tunnel
– Indented transition front observed in flight, not in ground test
– Wind tunnel transition at AoA biased to lower Reynolds compared to flight, but not as much as a=0
– Nosetip steps probably not contributor to this
• Additional results (not briefed)
– Leading-edge trip on HIFiRE-5 flight correlated with Redk
– Refined AoA & heating for HIFiRE-5 flight
7
HIFiRE-5 IR Transition Measurements
16 October 2015
Quiet, Re=12.3x106/m
Borg (AFRL), Purdue M=6 Quiet Tunnel
Steel forebody,
PEEK frustum
IR successful, Kulites do not significantly influence results
Flow
Instrumented Blank
8
Stationary Cross Flow Instability Growth
16 October 2015 Quantitative stationary crossflow measurement may be possible
Borg (AFRL), Purdue M=6 Quiet Tunnel
x=305.1 mm
9
Traveling Cross Flow Instability Growth
16 October 2015
Re=6.6x106/m Re=8.9x106/m
Re=9.9x106/m Re=12.8x106/m
Spatial growth observable
Borg (AFRL), Purdue M=6 Quiet Tunnel
10
Comparison With PSE
16 October 2015
Re=8.3x106/m
Re=8.9x106/m
LST/LPSE agree well with data at lower Reynolds
Lakebrink (Boeing), Borg (AFRL)
11
PSE Analysis - 8-deg M=6 Blunt Cone
Experiment
16 October 2015
Jewell (AFRL, NRC)
Small radius - high N-factors, ~7
Drop in N-factor when transition occurs within swallowing region
(similar to Marineaux)
1983 AF High-Reynolds M=6 tests
Effect of entropy-swallowing on transition
12
M=6 High-Reynolds Amplication Rates
16 October 2015
Jewell (AFRL, NRC)
- Second-mode freqs push PCB capabilities
- FLDI in works
2% bluntness
Re=20x106/ft
13
HIFiRE-1 SBLI
16 October 2015
Prabhu (NASA), Kimmel (AFRL)
Wind tunnel results useful for
calibrating turbulence models for
flight SBLI
14
HIFiRE-5 Heat Transfer Analysis
16 October 2015
f=0 f=90
t=20 sec t=32 sec
Miller, Kimmel (AFRL), Jewell (AFRL,
NRC)
Transverse
conduction
explains heating
discrepancies
15
HIFiRE-5 Pressure Measurements for
Flight Attitude
16 October 2015 Surface pressures suitable for attitude determination
Miller, Kimmel (AFRL), Jewell (AFRL, NRC)
AoA (deg)
Yaw
(d
eg
)
Ao
A (
de
g)
Ya
w (
de
g)
Min
% R
MS
Devia
tio
n
Time, sec
16
Summary
• HIFiRE-5 stability
– New IR transition measurement capability
– Traveling cross flow coexists with stationary
– Traveling detectable before stationary
– Before breakdown, phase speed and wave angle predicted
well with LPSE
• Cone at AoA / bluntness analysis
– Correlating N-factor drops when Retr drops
• HIFiRE flight analysis
– Tunnel - calibrated Reynolds stress model works well for
flight SBLI
– HIFiRE-5 pressure instrumentation as FADS works well
16 October 2015
17
Upcoming Work
16 October 2015
• IR calibration and stationary/traveling crossflow analysis (Borg) –
further insight into crossflow development
• Cone stability at AoA and bluntness effects (Jewell) – effect of strong
spanwise nonuniformity on instability development
• FLDI (Jewell, Lam) – measure freestream and boundary layer