WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Wake Vortex Encounter Gust Size
and Magnitude Flight Data
A P BrownFlight Research Laboratory,
NRC Aerospace
presented toWakeNet3-Europe 2nd Major Workshop
Developments in wake Turbulence SafetyToulouse, 28th/29th June, 2010
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Presentation
– Flight data (NRC program)
– Context of gust size/rise/fall-lengths and
magnitudes (gust peak speeds)
– Example of flight data
– Continuous turbulence
– Rise/fall analysis
– Discrete (turbulent trailing vortex cores)
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
CONTEXT – Proceeding to a definition of an acceptable WVE:
– Requires design & certification of structure, aeroservoelasticity, systems,
aerodynamics; in turn
– Requires definition of WVE gust magnitudes and rise-lengths, for
the formulation of design standards:-
– Discrete gusts, and
– Continuous gust spectra
– Combination (superposition)?
– Not presently required for aircraft gust-load certification
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
In which WVE realms:
– Both following realms are desirable:-
– Improvement upon existing landing-approach WT separation
standards, and
– Establishment of enroute WT separation standards
– both involve tWAKE O[40:120] seconds
– wake vortex trailing pair probably have turbulent cores,
may be in significant individual or/and mutual
instability state
– flight data has both dissipative turbulence scale
and intensifying turbulent scales, which are more
likely to be core instability modes
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
EXAMPLE – Trailing pair crossplane-
referenced vortex-induced wind perturbations
-60 -40 -20 0 20 40 60
-400
-300
-200
-100
0
100
0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 3 5 0 0 4 0 0 0 4 5 0 0- 3 0
- 2 0
- 1 0
0
1 0
2 0
3 0
d s o - s u m , b a s e d u p o n T A S & ψ
wc wa wZ
wc
wa
wZ
0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 3 5 0 0 4 0 0 0 4 5 0 00
5
1 0
1 5
2 0
2 5
3 0
d s o - s u m , b a s e d u p o n T A S & ψ
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Trailing pair crossplane
Continuous gust spectra
10-2
10-1
100
101
10-5
10-4
10-3
10-2
10-1
100
101
102
103
PSD of longitudinal gus tines s , vortex core travers es
s patial frequency (rad/ft)
continuous gust PSD (ft/s)2/(rad/ft))
flight data ,8-15 nm wake length, 53-90 s ec age
FAR25,App.F with Uσ=85 fps with σ=85/3.5 fps
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Continuous gust spectra
– FAR 25 for typical weight/dim 50-
70,000 lb transport a/c
10-2
10-1
100
101
10-5
10-4
10-3
10-2
10-1
100
101
102
PSD of lateral gus tines s , vortex core travers es
s patial frequency (rad/ft)
continuous gust PSD (ft/s)2/(rad/ft))
flight data,8-15 nm wake length, 53-90 s ec age
FAR25,App.F with Uσ=85 fps with σ=85/3.5 fps
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Continuous gust spectra
10-2
10-1
100
101
10-6
10-5
10-4
10-3
10-2
10-1
100
101
102
PSD of vertical gus tines s , vortex core travers es
s patial frequency (rad/ft)
continuous gust PSD (ft/s)2/(rad/ft))
flight data ,8-15 nm wake length, 53-90 s ec age
FAR25,App.F with Uσ=85 fps with σ=85/3.5 fps
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Rise and fall magnitudes & lengths
(peaks and troughs counting) of wCZ
1.08 1.085 1.09 1.095 1.1 1.105 1.11 1.115 1.12
x 105
0
5
10
15
20
25
0 5 10 15 20 25 30 350
2
4
6
8
10
12
14
16
18
gust-rise magnitude (m/s)
gus t-ris e length (m)
A380
Ris ing gus t
Falling gus t
Typ M FAR 12.5c/66fps ris e-rate
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
0.5
1
1.5
2
2.5
normalised gust-rise magnitude, VT/(
Γ/bV)
normalis ed gus t-ris e length, s /bGEN
A380
Rise and fall magnitudes & lengths
of wCZ normalised
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40
0.5
1
1.5
2
2.5
normalised gust-rise magnitude, VT/(
Γ/bV)
normalis ed gus t-ris e length, s /bGEN
A380
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
WVE - discrete vortex core
traverses:
Modelling of gust-rise/fall shape
– depends upon extent of
asymptotic VT rise
– examine flight data traverses
-25 -20 -15 -10 -5 0 5 10 15 20 25-30
-20
-10
0
10
20
30
dis tance (m)
VT ()m/s
1-cos
Burnham-Hallock
line vortex
s kewed 1-cos
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Vortex core traverses:
ΓGEN ≈≈≈≈ 735 m2/s
– Wake age, t = 53 sec
– Wake length 7.5 nm, Γ = 630 m2/s
– advance/recede tails overlay
– Superposition of mean + turbulent,
peak VT > 20 m/s (66 fps)
WVE Gust Magnitudes/Rise-lengths
0 5 10 15 20 25 30 350
5
10
15
20
25
30
rC m1/1
wCZ m/s
advance to vortex centre
recede from centre
5-15m B-H, Γ=682.9464 rC=3.7094
Rankine, Γ=628.5 rC=3.5
0.8 1 1.2 1.4 1.6 1.8 2-5
0
5
10
15
20
25
30
rC m1/5
wCZ m/s
advance to vortex centre
poly fit
recede from centre
5-15m B-H, Γ=682.9464 rC=3.7094
Rankine, Γ=628.5 rC=3.5
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
0 5 10 15 20 250
5
10
15
20
25
30
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
5-15m B-H, Γ=626.9098 rC=5.9714
Rankine, Γ=628.5 rC=3.5
Rankine, Γ=395.955 rC=3.7
Rankine, Γ=395.955 rC=2.9316
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 20
5
10
15
20
25
30
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=626.9098 rC=5.9714
Rankine, Γ=628.5 rC=3.5
Rankine, Γ=395.955 rC=3.7
Rankine, Γ=395.955 rC=2.9316
Vortex core traverse #2:
– Wake age, t = 58 sec
– Wake length 8 nm
– Γ = O[630] m2/s
– Sec features away from core edges
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
0 5 10 150
5
10
15
20
25
30
35
40
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
5-15m B-H, Γ=626.5063 rC=2.1544
Rankine, Γ=615.93 rC=2.7
Rankine, Γ=431.151 rC=2.7
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.80
5
10
15
20
25
30
35
40
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=626.5063 rC=2.1544
Rankine, Γ=615.93 rC=2.7
Rankine, Γ=431.151 rC=2.7
Vortex core traverse #3:
– Wake age, t = 60 sec
– Wake length 8.4 nm
– Γ = O[620] m2/s
– Lower turbulence, B-H models well
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Vortex core traverse #4:
– Wake age, t = 68 sec
– Wake length 9.5 nm
– Γ = O[600] m2/s
– large VT’ near core edge
0 5 10 150
5
10
15
20
25
30
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
B-H, for Γ=628.5 rC=4.5
Rankine, Γ=628.5 rC=4.5
1.1 1.2 1.3 1.4 1.5 1.6 1.70
5
10
15
20
25
30
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
B-H, for Γ=628.5 rC=4.5
Rankine, Γ=628.5 rC=4.5
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
0 1 2 3 4 5 6 7 8 90
5
10
15
20
25
30
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=260.9275 rC=1.3153
Rankine, Γ=62.8945 rC=0.37074
0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.60
5
10
15
20
25
30
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=260.9275 rC=1.3153
Rankine, Γ=62.8945 rC=0.37074
Vortex core traverse #5:
– Wake age, t = 74 sec
– Wake length 10.4 nm
– Γ = O[580] m2/s
– Secondary vortex, VT~r1/5 profile
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
0 0.5 1 1.5 2 2.5 30
5
10
15
20
25
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=64.3682 rC=0.5
Rankine, Γ=76.2643 rC=0.52773
0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.250
5
10
15
20
25
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=64.3682 rC=0.5
Rankine, Γ=76.2643 rC=0.52773
Vortex core traverse #6:
– Wake age, t = 76 sec
– Wake length 10.6 nm
– Γ = O[570] m2/s
– Secondary vortex
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
Vortex core traverse No.7:
– Wake age, t = 90 sec
– Wake length, 12.6 nm
– Γ = O[380] m2/s
0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.60
2
4
6
8
10
12
14
16
18
20
rC m1/5
wCZ m/s
advance to vortex centre
poly fit
recede from centre
5-15m B-H, Γ=309.6268 rC=2.3681
Rankine, Γ=309.6 rC=2.5
0 5 10 15 20 250
2
4
6
8
10
12
14
16
18
20
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
5-15m B-H, Γ=309.6268 rC=2.3681
Rankine, Γ=309.6 rC=2.5
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1
2
4
6
8
10
12
14
16
r m1/5
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=368.4531 rC=6
Rankine, Γ=368.4531 rC=6
0 5 10 15 20 25 30 35 40 45 500
2
4
6
8
10
12
14
16
18
r m1/1
wCZ m/s
advance to vortex centre
recede from centre
poly fit
5-15m B-H, Γ=368.4531 rC=6
Rankine, Γ=368.4531 rC=6
Vortex core traverse No.8:
– Wake age, t = 101 sec
– Wake length, 14.2 nm
– Γ = O[360] m2/s
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
– Have considered WVE gust size & magnitude 8-20nm wake survey flight data,
from the viewpoints of
– Continuous turbulence spectra loading, for helices around & through vortices
– Ώ(vZ) of the order of magnitude of FAR 25 design limit spectra; and
– Rise/fall peaks & troughs analysis (typ. For fatigue loading)
– groupings of gust rise/falls into a number of discrete non-dim rates
– Possibility of normalising by generator
– discrete vortex core traverse size/magnitude profiles
– Examined eight profiles in detail:- for each , mean + turbulent (VT’/VTO[50-100%) flow superposition evident; peak VT > 66 fps, FAR limit mag.
– Line vortex (Rankine) model, &
– Burnham-Hallock model – generally (7/8 times) under-estimated VT at
core edges – for the good ID, core traverse had low turbulence content;
– Line vortex model captured core edge VT augmentation by sec
vortices, implying non-dissipative in nature, core-stability driven?
– Further examination of existing & future data warranted.
Conclusions:– WVE, present & future occur with trailing
vortices likely turbulent, incl. cores
WVE Gust Size and Magnitude Flight Data
WakeNet, 3 EU, Toulouse, 28th/29th June, 2010
QUESTIONS?