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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Performance Analysis of Rotor Tip Shapes in Hover Using Computational Fluid Dynamics
Presented at the Burn 7-8 April 2006
by
Alan Brocklehurst and George Barakos
Rotor Systems, Aerodynamics
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
INTRODUCTION
Validation – UH-60A
Rotor Systems, Aerodynamics
Conclusions and Future Goals
Aims and Objectives
Comparison with Model TR Tests
Comparison Vortex Wake Trajectories
Tip Shapes - Vortex Wake Trajectories
Tip Shapes - Hover Performance
Loading and Downwash
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
AIMS AND OBJECTIVES
CFD starts from the conservation laws, and needs only Geometry Definition and Boundary (Flight) Conditions
Rotor Systems, Aerodynamics
Progress towards a high fidelity method for rotor designcapable of resolving subtle differences in tip shape
‘Work-in-progress’ towards PhD – Overlaps with WHL GoalsCurrent studies use Euler methods in Hover for economy
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
0.965R
CFD – Validation - UH-60A Model Tail Rotor Tests (Lorber)
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD – Validation - UH-60A Model Tail Rotor Tests (Lorber)
Rotor Systems, Aerodynamics
11.47o collective pitch, M tip =0.628, inviscid, 240-block grid, 4.5M grid points
Radial positionAxial position
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Comparison of CFD with Model Tail Rotor Tests from 1980/4
Rotor Systems, Aerodynamics
Rectangular Blade, NACA0012, 0,8,16 deg Twist, 0 deg Twist Considered Here
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Comparison of Euler CFD Predictionswith Model Rotor Test Data from 1980
Rotor Systems, Aerodynamics
Comparison with Model Rotor Thrust - Pitch Measurements Twisted Blades Test (1980), Mtip=0.492 (Vt=550 ft/s, 3000rpm)
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00
Impressed Pitch Referenced to Rotor Centre (deg)
Bla
de
Load
ing C
oef
fici
ent, C
T/s
Twist=0 Mtip=.492
Twist=8 Mtip=.492
Twist=16 Mtip=.492
Twist=0 Euler Fr Mtip=0.492
CFD predictions with zero coning,corrected for pitch-flap coupling
Comparison with Model Rotor Thrust - Pitch MeasurementsTwisted Blades Tests (1980), Mtip=0.263 (Vt=293ft/s,1600rpm)
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00
Impressed Pitch Referenced to Rotor Centre (deg)
Bla
de
Load
ing C
oef
fici
ent, C
T/s
Twist=0 Mtip=.263
Twist=8 Mtip=.263
Twist=16 Mtip=.263
Twist=0 Euler Fr Mtip=0.263
CFD predictions with coning, corrected for pitch-flap coupling
Rectangular Blade, NACA0012, Zero Twist
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
Comparison of Euler CFD Predictions with Model Tail Rotor Tests from 1984
Comparison with Model Tail Rotor Thrust - Pitch MeasurementsTests 1980, Mtip=.263, and 'Fin-Blockage' Tests (No Fin)1984, Mtip=0.361
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00
Impressed Pitch (degrees)
Bla
de L
oadi
ng
Coef
ficie
nt,
CT/
s
Test (1980) Mtip=.263
Test (1984) Mtip=.361
CFD Euler Mtip=.263
CFD Euler Mtip=0.492
Zero Twist
All predictions corrected for pitch-flap coupling
Comparison with Model Tail Rotor Thrust - Power Measurements'Fin-Blockage' Tests (No Fin) 1984, Mtip=0.3610
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.000 0.010 0.020 0.030 0.040 0.050 0.060
Rotor Thrust Coefficient, CT
Roto
r Torq
ue
Coef
fici
ent, C
Q
Twist=0 Mtip=.361 1984
Twist=0 CFD Euler M=0.263
Twist=0 CFD Euler M=0.492
Mom Theory CDo=.018, ki=1.4
Rectangular Blade, NACA0012, Zero Twist
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
Comparison of CFD and Model Tail Rotor Vortex Wake Trajectories
Vertical Sections at 0 degrees wake age
Model Rotor Flow Visualisation
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
Comparison – Model Tail Rotor – Vortex Wake Trajectories (1)Comparison of CFD and Experiment
Vortex Locations - Vertical Displacement
-0.600
-0.500
-0.400
-0.300
-0.200
-0.100
0.000
0 30 60 90 120 150 180 210 240 270 300 330 360
Vortex Age (deg of azimuth)
Ver
t D
ispla
cem
ent, z
v/R
(re
l to tip
)
Test (WHL, 1980), 5 degrees pitch
Test (WHL, 1984), 8 degrees pitch
Test (WHL, 1980), 10 degrees pitch
Test (WHL, 1980), 15 degrees pitch
CFD TRB-0100 5 deg CT=.00598
CFD TRB-0100 8 deg CT=.01190
CFD TRB-0100 10 deg CT=.01723
CFD TRB-0100 15deg CT=.03401
Kocurek and Tangler CT=.00598 (5 deg)
Kocurek and Tangler CT=.01190 (8 deg)
Kocurek and Tangler CT=.01723 (10deg)
Kocurek and Tangler CT=.03401 (15deg)
TRB-0100 Rectangular Blade, Zero Twist, Mtip=0.263
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
Comparison – Model Tail Rotor – Vortex Wake Trajectories (2)Comparison of CFD and Experiment
Vortex Locations - Contraction
0.000
0.050
0.100
0.150
0.200
0.250
0 30 60 90 120 150 180 210 240 270 300 330 360
Vortex Age (deg of azimuth)
Contr
action (1-
xv/R
)
Test (WHL, 1980), 5 degrees pitch
Test (WHL, 1984), 8 degrees pitch
Test (WHL, 1980), 10 degrees pitch
Test (WHL, 1980), 15 degrees pitch
CFD TRB-0100 5 deg CT=.00598
CFD TRB-0100 8 deg CT=.01190
CFD TRB-0100 10 deg CT=.01723
CFD TRB-0100 15 deg CT=0.03401
Kocurek and Tangler CT=.00598 (5 deg)
Kocurek and Tangler CT=.01190 (8 deg)
Kocurek and Tangler CT=.01723 (10deg)
Kocurek and Tangler CT=.03401 (15deg)
TRB-0100 Rectangular Blade, Zero Twist, Mtip=0.263
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
Comparison – Model Tail Rotor – Vortex Wake Trajectories (3)Comparison of CFD and Experiment
Vortex Locations - Trajectory
-0.600
-0.500
-0.400
-0.300
-0.200
-0.100
0.000
0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000
Radial Location, xv/R (shifted)
Ver
t D
ispla
cem
ent, z
v/R
(re
l to tip
)
Test (1980), 5 degrees pitch
Test (1984), 8 degrees pitch
Test (1980), 10 degrees pitch
Test (1980), 15 degrees pitch
CFD TRB-0100 5 deg CT=.00598
CFD TRB-0100 8 deg CT=.01190
CFD TRB-0100 10 deg CT=.01723
CFD TRB-0100 15 deg CT=.03401
Kocurek and Tangler CT=.00598 (5 deg)
Kocurek and Tangler CT=.01190 (8 deg)
Kocurek and Tangler CT=.01723 (10deg)
Kocurek and Tangler CT=.03401 (15deg)
TRB-0100 Rectangular Blade, Zero Twist, Mtip=0.263
5 deg
10 deg
8 deg
15 deg
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis – Mtip=0.6
Rotor Systems, Aerodynamics
Thrust, Power, Pitch and and Figure of Merit
Vortex Wake Comparisons
Blade Loading and Downwash Distribution
Different Tip Shapes and Anhedral
TRB-004 Rectangular Tip, 20 deg Anhedral,10 deg Pitch – Iso-surfaces of Vorticity Magnitude
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
TRB-000 Rectangular Tip, Datum Blade TRB-001 Kuchemann (1/4c wide) Tip
TRB-002 Kuchemann (1/2c wide) TipTRB-004 Rectangular Tip, 20 deg Anhedral
Euler Hover using HMB (no coning)
Mtip=0.6 Pitch=10 deg
Root 33%R
Root 33%R
Root 33%R
Root 33%R
Tip100%R
Tip100%R
Tip100%R
Tip100%R
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
TRB-000 Rectangular Tip Datum Blade
TRB-001 Kuchemann Tip(1/4c wide)
TRB-002 Kuchemann Tip(1/2c wide)
TRB-004 Rectangular Tip20 deg Anhedral
Euler Hover using HMB
All Tips at 14 deg Pitch (no coning)
Mtip=0.6
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor PerformanceThrust vs Pitch - Hover - HMB Euler - Mtip=0.6
0.00
0.01
0.02
0.03
0.04
0.05
0.0 5.0 10.0 15.0 20.0 25.0 30.0
Blade Pitch Angle (deg)
Roto
r Thru
st C
oef
fici
ent, C
T
TRB-000 (Rectangular)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular + Anhedral)
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor PerformanceTorque vs Thrust - Hover - HMB Euler - Mtip=0.6
0.0000
0.0010
0.0020
0.0030
0.0040
0.0050
0.0060
0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050
Rotor Thrust Coefficient, CT
Roto
r Torq
ue Coef
ficien
t, C
Q
TRB-000 (Rectangular)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchmann)
TRB-004 (Rectangular + Anhedral)
Induced, ki= 1.3
14deg
6deg
8deg
10deg
12deg
3deg4deg
15deg
16deg
5deg
2deg
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor PerformanceTorque vs Thrust1.5 - Hover - HMB Euler - Mtip=0.6
0.0000
0.0005
0.0010
0.0015
0.0020
0.0025
0.0030
0.0035
0.0040
0.0045
0.0050
0.0000 0.0010 0.0020 0.0030 0.0040 0.0050
(Rotor Thrust Coefficient)1.5, CT1.5
Ro
tor
To
rqu
e C
oef
fici
ent,
CQ
T R B -000 (R ectangu la r)
T R B -001 (.25c K uchem ann)
T R B -002 (.5c K uchemann )
T R B -004 (R ectangu la r + Anhedra l)
Induced, k i= 1 .3
6deg
8deg
10deg
12deg
4deg
2deg
TRB-000 ki=1.397TRB-001 ki=1.370TRB-002 ki=1.400TRB-004 ki=1.336
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor Performance Blade 'Profile' Drag - Hover - HMB Euler - Mtip=0.6
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.00 0.01 0.02 0.03 0.04 0.05
Rotor Thrust Coefficient, CT
Inte
gra
ted B
lade
Dra
g C
oef
fici
ent, C
de
TRB-000 (Rectangular)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular + Anhedral)
14deg
6deg
8deg 10deg 12deg
3deg
4deg
15deg
16deg
17deg
5deg
2deg
TRB-000 ki=1.397TRB-001 ki=1.370TRB-002 ki=1.400TRB-004 ki=1.336
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor PerformanceFigure of Merit - Hover - HMB Euler - Mtip=0.6
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050
Rotor Thrust Coefficient, CT
Fig
ure
of M
erit, F
oM TRB-000 (Rectangular)
TRB-000 (+CDsf=.008)
TRB-001 (.25c Kuchemann)
TRB-001 (+CDsf=.008)
TRB-002 (.5c Kuchemann)
TRB-002 (+CDsf=.008)
TRB-004 (Rectangular + Anhedral)
TRB-004 (+CDsf=.008)
Induced, ki= 1.3
with constant CD= 0.01
14deg
6deg
8deg
10deg12deg
2deg
4deg
14deg6deg
8deg 10deg 12deg
2deg
4deg17deg16deg15deg
17deg16deg15deg
3deg
5deg
3deg
5deg
TRB-000
TRB-002
TRB-004
(20deg anhedral)
Inviscid, Euler
Euler + CDsf=.008
TRB-001
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Tip Shapes – CFD Performance Analysis
Rotor Systems, Aerodynamics
Effect of Tip Shape on Rotor Performance'Thrust/Power' Ratio - CT/CQ - Hover - HMB Euler - Mtip=0.6
5.00
10.00
15.00
20.00
0.0 5.0 10.0 15.0 20.0
Blade Pitch Angle (deg)
'Thru
st/P
ow
er' R
atio
, CT/C
Qe
TRB-000 (Rectangular)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular + Anhedral)
If desired, multiply CT/CQ by 0.82065to get lb/hpfor this rotor
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Effect of Tip Shapes on Vortex Wake Trajectories
Euler HoverMtip=0.64 Tip shapescompared
Rotor Systems, Aerodynamics
Radius
Z
0 2 4 6 8-6
-4
-2
0
2TRB-000Mtip=0.6
ZeroTwist,ZeroConing10degpitch
VorticityContoursSectionthroughbladerefaxis
V2age=90deg
V3age=180deg
V4age=270deg
V1age=360deg
V1age=0deg
S2
S3
S4
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD- Tip Shapes – Wake Trajectories (1a)
Rotor Systems, Aerodynamics
Comparison of Computed Vortex Wake Vertical Displacements in Hover Blade Pitch Angle=10 degrees, Mtip=0.6
-0.500
-0.450
-0.400
-0.350
-0.300
-0.250
-0.200
-0.150
-0.100
-0.050
0.000
0 50 100 150 200 250 300 350 400
Vortex Age (degrees)
Ver
t D
ispla
cem
ent, z
v/R
TRB-000 (Rectangular, datum)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular+Anhedral)
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD- Tip Shapes – Wake Trajectories (1b)
Rotor Systems, Aerodynamics
Comparison of Computed Vortex Wake Vertical Displacements in Hover Blade Pitch Angle=10 degrees, Mtip=0.6
-0.120
-0.100
-0.080
-0.060
-0.040
-0.020
0.000
0 20 40 60 80 100 120
Vortex Age (degrees)
Vert Displace
men
t, zv/R
TRB-000 (Rectangular, datum)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular+Anhedral)
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD- Tip Shapes – Wake Trajectories (2a)
Rotor Systems, Aerodynamics
Comparison of Computed Vortex Wake Contraction in Hover Blade Pitch Angle=10 degrees, Mtip=0.6
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0 50 100 150 200 250 300 350 400
Vortex Age (degrees)
Contr
action (1-
xv/R
)
TRB-000 (Rectangular, datum)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004(Rectangular+Anhedral)
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD- Tip Shapes – Wake Trajectories (2b)
Rotor Systems, Aerodynamics
C o m p a r i s o n o f C o m p u t e d V o r t e x W a k e C o n t r a c t i o n i n H o v e rB l a d e P i t c h A n g l e = 1 0 d e g r e e s , M t i p = 0 . 6
0 . 0 0 0 0
0 . 0 2 0 0
0 . 0 4 0 0
0 . 0 6 0 0
0 . 0 8 0 0
0 . 1 0 0 0
0 . 1 2 0 0
0 . 1 4 0 0
0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0
V o r t e x A g e ( d e g r e e s )
Co
ntr
acti
on
(1-
xv/R
)
T R B - 0 0 0 ( R e c t a n g u l a r , d a t u m )
T R B - 0 0 1 ( . 2 5 c K u c h e m a n n )
T R B - 0 0 2 ( . 5 c K u c h e m a n n )
T R B - 0 0 4( R e c t a n g u l a r + A n h e d r a l )T e s t 1 0 d e g
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD- Tip Shapes – Wake Trajectories (3)
Rotor Systems, Aerodynamics
Comparison of Computed Vortex Wake Trajectories in Hover Blade Pitch Angle=10degrees, Mtip=0.6
-0.20
-0.15
-0.10
-0.05
0.000.70 0.75 0.80 0.85 0.90 0.95 1.00
Horizontal Location, xv/R
Vert Displacement, zv/R
Test (Mtip=.263)
TRB-000 (Rectangular, datum)
TRB-001 (.25c Kuchemann)
TRB-002 (.5c Kuchemann)
TRB-004 (Rectangular+Anhedral)
Euler CFD , no coning
90 deg age
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD - Tip Shapes (000, 001, 002) – Visualisation
Rotor Systems, Aerodynamics
Radial Location
Z/R
0.85 0.9 0.95 1-0.15
-0.1
-0.05
0
TRB-002 (1/2cwideKuchemannTip), Mtip=0.6, Pitch=10degVorticesat 10degreesbehindblade
Radial Location
Z/R
0.85 0.9 0.95 1-0.15
-0.1
-0.05
0
TRB-001 (1/4cwide KuchemannTip), Mtip=0.6, Pitch=10degVorticesat 10degbehindblade
Radial Location
Z/R
0.85 0.9 0.95 1-0.15
-0.1
-0.05
0
TRB-000 (Rectangular, Datum) Mtip=0.6 Pitch=10degVorticesat 10 degreesbehindblade
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD - Tip Shapes (000, 004) – Visualisation - Anhedral
Rotor Systems, Aerodynamics
RadialLocation
Z/R
0.85 0.9 0.95 1-0.15
-0.1
-0.05
0
TRB-000 (Rectangular, Datum) Mtip=0.6 Pitch=10degVorticesat 10 degreesbehindblade
Radial Location
Z/R
0.85 0.9 0.95 1
-0.15
-0.1
-0.05
0
TRB-004 (Rectangular+ Anhedral), Mtip=0.6, Pitch=10degVorticesat 10degbehindthe blade
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD - Tip Shapes - Wake Trajectories – Anhedral (1)
Rotor Systems, Aerodynamics
Comparison of Computed Vortex Displacements Near Blade Tip in Hover Effect of Anhedral - Blade Pitch Angle=10deg, Mtip=0.6
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
-15 -10 -5 0 5 10 15 20
Azimuth Angle Relative to Blade Ref Axis (degrees)
Ver
tica
l Dis
pla
cem
ent, z
v/R
TRB-000 (Rectangular,Datum)
TRB-000 Geometry
TRB-004 (Rectangular+Anhedral)
TRB-004 Geometry
L.E.
T.E.
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
Rotor Systems, Aerodynamics
CFD - Tip Shapes - Wake Trajectories – Anhedral (2)Comparison of Computed Vortex Contraction Near Blade Tip in Hover
Effect of Anhedral - Blade Pitch Angle=10deg, Mtip=0.6
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
-15 -10 -5 0 5 10 15 20
Azimuth Angle Relative to Blade Ref Axis (degrees)
Rad
ial D
ispla
cem
ent, (1-
xv/R
)
TRB-000 (Rectangular, Datum)
TRB-000 Geometry
TRB-004 (Rectangular+Anhedral)
TRB-004 Geometry
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Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD Analysis – Loading Distribution
Rotor Systems, Aerodynamics
TRB-000 Mtip=0.6 10 deg PitchCT=.0199 Ct/s=0.100
Pressure Distribution in Tip RegionThrust Distribution
0
0.1
0.2
0.3
0.4
0.5
0.6
0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95
Radial Location, r/R
Load
ing, C
z*x2
TRB-000 Mtip=0.6 10deg
Moment Distribution
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95
Radial Location, r/R
Aer
odyn
amic
Mom
ent C
oef
fici
ent, C
m.x
2
TRB-000 Mtip=0.6 10deg
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CFD Analysis - Tip Shapes – Downwash
Rotor Systems, Aerodynamics
TRB-000 Mtip=0.6 10 deg PitchCT=.0199 Ct/s=0.100
Downwash DistributionIn a horizontal plane0.25c below the rotor
Westland Helicopters is an AgustaWestland Company
Helicopter Rotor Tip Shapes in Hover
Department of EngineeringRotor Systems, AerodynamicsUniversity of Liverpool
CONCLUSIONS AND FUTURE GOALS
CFD method has been validated against UH-60A dataand by comparison to model tail rotor measurements
Rotor Systems, Aerodynamics
Vortex Wake – Euler - better than expected – N-S?
Progress to Navier-Stokes for even more realistic rotor (tip) design evaluations
CFD has been used to determine the effect of tip shape on rotor performance (induced power) in hover
Investigate effect of tip shape on loading and downwash