Advanced Aerodynamic Analysis of the NASA High-

Lift Trap Wing with a Moving Flap Configuration

Matt Hieatt

• Introduction

• Numerical Methodology

• 1st High Lift Prediction Workshop and Results

• Polar Sweep

• Stowing and Un-Stowing

• Summary

Outline

2

XFlow is a CFD software specifically designed to simulate complex systems

with highly transient flows and the presence of moving parts

These two areas have traditionally proven to be difficult to treat with classic

FEM/FVM schemes

Introduction

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• Inspired by the kinetic theory of gases

The kinetic theory of gases is a physical theory that explains the macroscopic behavior and properties of gases from a statistical description of the microscopic molecular processes (L. Boltzmann, J.C. Maxwell, s. XIX)

• Solves the Boltzmann equation across an octagonal grid

• The fluid is represented as particle distribution functions (PDFs) of linear momentum and density

Streaming Transport of the PDF’s to surrounding points

Distribution Models the Interaction and scatter of molecules to recalculate the PDF’s

Lattice-Boltzmann Method

Lattice-Boltzmann Method

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• No meshing required

• Inherently transient and compressible

• Solves Large Eddy Simulation to resolution of the grid

• Dynamically increases resolution to capture turbulence

• Automatically detects geometry and applies

advanced wall model (fixed or moving)

• Introduction

• Numerical Methodology

• 1st High Lift Prediction Workshop Results

• Polar Sweep

• Stowing and Un-Stowing

• Summary

Outline

6

• Trap wing "Config 1" (slat 30, flap 25)

• Mach = 0.2

• Reynolds = 4.3E+6 based on MAC

• Mean aerodynamic chord = 1.0067 m

• AoA: -4, 1, 6, 13, 21, 28, 32, 34 and 37 degrees

1st High Lift Prediction Workshop Results

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All the computations were run on a single workstation with twoprocessors Intel Xeon E5620 @ 2.4 GHz (8 cores) and 12GB of RAM

The American Institute of Aeronautics and Astronautics (AIAA)is the world'slargest technical society dedicated to the global aerospace profession

The 1st AIAA CFD High Lift Prediction Workshop1 (HiLiftPW-1) took place inJune 2010,provided a reference benchmark for the aeronautical industry, totest commercial CFD software packages.

1st High Lift Prediction Workshop Results

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Virtual wind tunnel configuration: ( 40 x 15 x 30 ) m

Far field velocity as initial boundary condition

Slip plane on the boundary wall

Periodic Boundaries elsewhere

Model Set up

Lattice Size and Convergence Study

Spatial discretization

Each refinement level solves spatial and temporal scales two times smaller than theprevious level

Resolved scale = h Resolved scale = h/2 Resolved scale = h/4

Resolved scale = h and target scale near walls = h/4

1st High Lift Prediction Workshop Results

1st High Lift Prediction Workshop Results

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Adaptive wake refinement

Lattice size and Convergence study

Confidential 11

Lattice size and Convergence study

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CaseMach

numberReynolds number

MAC (m)

Simulationtime (s)

Theoricalboundary layer thickness (m)

Farfieldrefinement

(m)

Near wallrefineme

nt (m)

Wake refinemen

t (m)

Numberelement

Cells # onMAC

Cells # in boundary

layer

Cells # onFarfield (x direction)

HL1 0.2 4.30E+06 1.0067 0.3 0.0181 1.28 0.01 0.02 2.89E+06 100.67 1.81 31.25

HL2 0.175 1.50E+07 0.34709 0.1 0.0049 5.12 0.005 - 1.50E+08 69.41 0.97 7.81

HL2 0.175 1.51E+08 0.34709 0.1 0.0031 5.12 0.005 - 1.50E+08 69.41 0.61 7.81

HTP forward 0.2 1.90E+06 0.431 0.5 0.0091 1.28 0.005 0.01 7e6 to 35e6 86.20 1.83 31.25

UAV 0.1 1.50E+06 0.69 0.5 0.0153 1.28 0.01 0.02 5.00E+06 69 1.53 46.87

Recommended values:

Lattice nodes on MAC ≈ 85 lattices

Lattice nodes in boundary layer ≈ 1.5 lattices

Lattice nodes in the Farfield x-direction ≈ 20 lattices

Wake refinement twice wing refinement

Aerospace “Hygiene” Rules

1st High Lift Prediction Workshop Results

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Volume rendering of the vorticity module for AoA = 13º

1st High Lift Prediction Workshop Results

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1st High Lift Prediction Workshop Results

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1st High Lift Prediction Workshop Results

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Volume rendering of the vorticity module for AoA = 37º

• Introduction

• Numerical Methodology

• 1st High Lift Prediction Workshop Results

• Polar Sweep

• Stowing and Un-Stowing

• Summary

Outline

17

Sweep from the linear part of the polar to the stall region

Polar Sweep

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Polar Sweep

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Sweep from the linear part of the polar to the stall region

Polar Sweep

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Polar Sweep

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• Introduction

• Numerical Methodology

• 1st High Lift Prediction Workshop Results

• Polar Sweep

• Stowing and Un-Stowing

• Summary

Outline

22

Stowing and Un-Stowing

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Stowing and Un-Stowing

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Volume rendering of the vorticity module

Stowing and Un-Stowing

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Volume rendering of the vorticity module

Stowing and Un-Stowing

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• Results for the 1st HLPWF in good agreement with experimental

data

• XFlow has been proved a reliable tool for traditional and advanced

aerodynamic problems involving presence of moving parts

• Successful polar sweep simulation

• Proof of concept simulation for the stowing and un-stowing

maneuvers shows interesting results

Summary

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Introduction

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