High-Lift Aerodynamics:

STAR-CCM+ Applied to

AIAA HiLiftWS1

D. Snyder

Aerodynamics – Subsonic through Hypersonic

– Aeroacoustics

– Store release & weapons bay analysis

– High lift devices

– Stage separation

– Plume analysis

– Ablation

– Engine integration

Aerospace Application Areas

Aerodynamics – Subsonic through Hypersonic

– Aeroacoustics

– Store release & weapons bay analysis

– High lift devices

– Stage separation

– Plume analysis

– Ablation

– Engine integration

Propulsion Systems – Pumps

– Rocket Motor, Ramjet, & Scramjet

– Fans and Turbines

– Combustion, sprays, chemistry

– Inlets & ducting

– Nozzles

– Fuel systems, sloshing

– Filters

Aerospace Application Areas

Aerodynamics – Subsonic through Hypersonic

– Aeroacoustics

– Store release & weapons bay analysis

– High lift devices

– Stage separation

– Plume analysis

– Ablation

– Engine integration

Propulsion Systems – Pumps

– Rocket Motor, Ramjet & Scramjet

– Fans and Turbines

– Combustion, sprays, chemistry

– Inlets & ducting

– Nozzles

– Fuel systems, sloshing

– Filters

Heat Transfer and Thermal

Management – Mechanical Systems

(APU’s, undercowling, etc.)

– Ice Protection

– Avionics / Electronics Systems

– Battery Heat Management

– Heat Exchangers

– Blade cooling

– Other Conjugate Heat Transfer

Aerospace Application Areas

Aerodynamics of 3D swept wings in high-lift configurations is very

complex

– Separation

– Unsteadiness

– Confluent boundary layers

– Transition

– Vortical flow

AIAA HiLiftWS1 (2010)

– Assess capabilities of

current-generation codes

• Meshing

• Numerics

• Turbulence Modeling

• High-performance computing

High-Lift Aerodynamics

Tested in 1998-1999, 2002-2003 at

NASA Langley and NASA Ames wind

tunnels

Re ~ 4.6M

– No turbulent trips – transition is a

factor

Data collected

– Aerodynamic forces/moments*

– Pressure distributions*

– Transition location

– Acoustics

NASA ‘Trap Wing’ Model

*Evaluated in HiLiftWS1

Trap Wing in NASA LaRC 14x22 WT

Geometry provided in IGES format

– Minor surface cleanup

“Configuration 1”

– Slats at 30 deg, Flaps at 25 deg

– Fully-deployed configuration

Farfield boundaries created in STAR-CCM+

– Extend 100MAC in all directions

Computational Domain

No-slip wall conditions

– No transition location specified

Symmetry plane

Freestream

– Mach 0.2

– T = 520R

– P = 1 ATM

– (Re = 4.3M based on MAC)

– a = 6, 13, 21, 28, 32, 34, 35,

36, 37 deg

Boundary Conditions

Polyhedral mesh

– Wide range of angles of attack on

a single mesh

– Strong streamline curvature

– Massive recirculation regions

Prism layers

– 30 layers

Grid refinement study

– Results from Medium grid are

presented

Mesh Overview

Grid Size Number of cells

Very Coarse 10M Coarse 21M Medium 34M

Fine 43M

*Very Coarse mesh shown (10M cells)

Text

Additional Mesh Features

*Very Coarse mesh shown (10M cells)

Density-Based Coupled Solver

– Low Mach number preconditioning

2nd-order spatial discretization

Steady-state RANS equations

SST (Menter) k-w Turbulence Model

– Integrated to the wall

– 1st prism layer y+ < 1.0

– g-Reθ Transition Model

Solver Settings

g-Reθ Transition Model

– Predicts laminar-turbulent transition in the boundary layer

– Correlation-based model formulated for unstructured CFD codes

– Models transport of Momentum Thickness Re and Intermittency

Without transition modeling

– Lift coefficient generally underpredicted

– Stall predicted too late

Transition Model

Transition AoA=13°

Convergence Behavior

0

0.5

1

1.5

2

2.5

3

3.5

0 2000 4000 6000 8000 10000 12000 14000

CL

Iterations (n)

6 degrees13 degrees21 degrees28 degrees32 degrees34 degrees

Turn on transition model

*At higher angles of attack, stability required running without transition model for a time.

Complex Flowfield

AOA=6 AOA=13

AOA=37 AOA=28

Lift Prediction

0

0.5

1

1.5

2

2.5

3

3.5

-5 0 5 10 15 20 25 30 35 40

CL

Angle of Attack (Degrees)

Configuration 1

Experiment

STAR-CCM+: Medium

Lift Prediction

0

0.5

1

1.5

2

2.5

3

3.5

-5 0 5 10 15 20 25 30 35 40

CL

Angle of Attack (Degrees)

Configuration 1

Experiment

STAR-CCM+: Medium

Drag Prediction

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-5 0 5 10 15 20 25 30 35 40

CD

Angle of Attack (Degrees)

Experiment

STAR-CCM+: Medium

Pitching Moment Prediction

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

-5 0 5 10 15 20 25 30 35 40

CM

Angle of Attack (Degrees)

Experiment

STAR-CCM+: Medium

Pressure measurements were made at ~800 locations on the wing

surface

Similarly, CFD data was extracted at 9 corresponding spanwise locations

Pressure Data

0.17

0.28

0.41

0.50

0.65

0.70

0.85

0.95

0.98

Experimental pressure tap locations CFD data extraction

locations

Cp Comparison: η=0.50 (mid-span)

AoA=6° AoA=21°

AoA=34° AoA=37°

Cp Comparison: η=0.95 (tip)

AoA=6° AoA=21°

AoA=34° AoA=37°

STAR-CCM+ accurately predicted the

aerodynamic behavior of the NASA ‘Trap

Wing’ high-lift case

– Lift, drag, and pitching moment

– Pressure distribution

Proper meshing techniques were important

– Boundary layer

– Element wake interactions

– Massive separation region

– Tip vortex

Transition modeling was necessary

– Fully-turbulent under-predicted lift at high AoA

(pre-stall)

– Fully-turbulent over-predicted stall AoA

Conclusions

AoA=6°

AoA=21°

HiLiftWS1 Special Session

(June 2012)

– Addition of support brackets

– Hysteresis effects

Aeroelastic Prediction Workshop (April

2012)

Propulsion Aerodynamics Workshop

(July 2012)

Eglin Store Separation Validation

Upcoming

Questions?