ATLAS Aero Team - UPat ATLAS-V Design

2D Biplane CFD Results - Phase I

Spyridon Kontogiannis and Alexandros Kontogiannis

January 8, 2015

For the first phase of the CFD analysis the 2D Biplane arrangement with g=1, st=0.3 anddecalage=-3o with the S1210 airfoil was tested. The analysis was held with S-A and SST k-models using Fluent for the Reynolds number of 200k while the mesh was constructed usingGambit. The forces on the biplane airfoils were investigated for angles ranging from 0 to 14o

with a step of 2o.

In the next pages there is a brief report consisting mainly of plots and screenshots of thedata. The following are included:

Coefficient plots of pressure, lift, drag and moment.

Qualitative data of the static pressure, velocity field, turbulent kinetic energy, velocityprofile of BL and the pre-stall characteristics.

The purpose of this analysis was to validate that the arrangement is efficient and to providemore accurate results to account for viscous effects. The results were promising (high clmax,relatively low cd and cm for the operational angles and high stall angle) and the arrangementis considered fixed.

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Mesh with Gambit

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Cp Distributions

Spalart-Allmaras (1st order upwind discr. scheme)

- 2o Angle

- 4o Angle

- 6o Angle

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Spalart-Allmaras (2nd order upwind discr. scheme)

- 2o Angle

- 4o Angle

- 6o Angle

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SST k-omega (1st order upwind discr. scheme)

- 2o Angle

- 4o Angle

- 6o Angle

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SST k-omega (2nd order upwind discr. scheme)

- 2o Angle

- 4o Angle

- 6o Angle

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Lift Coefficient vs Angle

0 2 4 6 8 10 12 141

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

22D BIPLANE ANALYSIS g=1, st=0.3, dec=-3 S1210

Angle (deg)

LiftCoeffi

cient

SA 1st ord. upw.SA 2nd ord. upw.SSTkw 1st ord. upw.SSTkw 2nd ord. upw.

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Lift Coefficient vs Drag Coefficient

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.161

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

22D BIPLANE ANALYSIS g=1, st=0.3, dec=-3 S1210

Drag Coefficient

LiftCoeffi

cient

SA 1st ord. upw.SA 2nd ord. upw.SSTkw 1st ord. upw.SSTkw 2nd ord. upw.

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Moment Coefficient vs Angle

0 2 4 6 8 10 12 140.06

0.08

0.1

0.12

0.14

0.16

0.18

0.22D BIPLANE ANALYSIS g=1, st=0.3, dec=-3 S1210

Angle (deg)

Mom

entCoeffi

cient[CG:(142mm,0,145mm)]

SA 1st ord. upw.SA 2nd ord. upw.SSTkw 1st ord. upw.SSTkw 2nd ord. upw.

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Qualitative Data

S-A - Contours of Static Pressure at 4o

S-A - Velocity Field at 4o

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SST k-omega - Turbulent Kinetic Energy (k) at 4o

0.4cTransition

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Boundary Layer

S-A - Fully Turbulent Velocity Profile at 8o

Turbulent BL/ Velocity Profile

SST k-omega - Laminar to Turbulent Velocity Profiles at 8o

Reverse Flow and TransitionLaminar Flow

Turbulent Flow

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Pre-Stall Characteristics

SST k-omega - Laminar Separation Bubble of upper airfoil at 14o

Laminar Separation Bubble

S-A - No Laminar Separation Bubble on upper airfoil at 14o

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SST k-omega - Laminar Separation Bubble of lower airfoil at 14o

SST k-omega - Transition and LSB of lower airfoil at 14o

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