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Mano Prakash R., Manoj Kumar B., Lakshmi Narayanan

Applied Aerodynamics Conference Modelling & Simulation In The Aerodynamic Design Process

BRISTOL / 17 - 19 JULY 2012

Aerodynamic Performance Analysis of A Non Planar C Wing using Experimental

and Numerical Tools

Outline 1 Introduction

2 Computational Fluid Dynamics

3 Wind tunnel Testing

5

6 Conclusions and Recommendations

Radio – Controlled model

4 Induced drag comparison

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Outline 1 Introduction

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Introduction  

Accounts for 80% – 90% of the aircraft’s climb drag.

Possible ways of reduction:

Increased span (Weight!)

Non planar concepts - Winglets, C wing, etc.

Thrust required curve for jet aircraft4/28

Objective To perform force (lift and drag) measurements on a

C-wing with a NACA 0012 profile at different angles of attack and compare the results obtained to those corresponding to a conventional plane rectangular wing.

To incorporate a C-wing into a remote controlled aircraft that can be maneuvered using the ailerons mounted on the C-wing.

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Methodology To carry out CFD analyses on C wing geometries to finalize

the wind tunnel model based on optimum lift/drag ratio.

Front view Right side view6/28

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Outline

2 Computational Fluid Dynamics

CFD3D Inviscid flow simulation

Tools employed:

CATIA V5 is used for 3D models.

Grid generation for the models is carried out using

ANSYS Workbench.

Flow computations are performed using ANSYS CFX.

Postprocessing is carried out using CFD Post.

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Initial GeometryModel 1

Selection Criteria: Reference wing dimensions -Span = 500mm, Chord = 150mm, Aspect Ratio = 3.33

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Surface grids

Coarse Medium Fine

12782950Elements: 5626709 8757321

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Grids -Cut Section at 50% of span

Coarse Medium Fine

1.2 1.1 1.05Growth

rate

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Flow Field ConditionsReynolds Re = 3 × 105 based on chord, c = 0.13m and Number

flow velocity, V∞ = 35m/s

Mach number, M∞ = 0.1

Turbulence model = Laminar

Inlet = Velocity, V∞ = 35m/s

Outlet = Pressure, P = 0atm

Walls = Free slip wall

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Force convergence

M∞ = 0.1, Re∞ = 3 × 105, α = 5o

CFD Results

Force coefficients do not asymptote on fine grid.13/28

Span1 Span2 Height1 702 753 804 855 425 1506 430 1457 435 1408 440 135

85

Dimensions (mm)Model

420 155

Final model

α

𝐿𝐷

Lift / Drag Vs. Angle of attack

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Outline

3 Wind tunnel Testing

Wind tunnel Subsonic wind tunnelHindustan College Of Engineering, Anna University, Chennai, India.

Tunnel type :

Open loop tunnel

Test section :

60cm × 60cm × 200cm

Velocity range:

0 – 80m/s

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Experimental set upModel

Material used:Fiberglass

Total pressure taps: 32

Manufacturing accuracy: ± 0.00012mm

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Results

𝐿𝐷

α

𝐿𝐷

α

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Outline

4 Induced drag comparison

 

Planar wing

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C-wing

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Interference factor b1 = 435mm b2 = 140mmh = 85mmb2/b1 = 0.32h/b1 = 0.2σ = 0.197 σ* = 0.98

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Comparison curve

α

𝑪𝑫𝑰

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Outline

5 Radio – Controlled model

ModelMaterials:Fuselage - Spad board reinforced with balsa wood.

Wing and tail plane - Coroplast reinforced with balsa wood.

Controls:Speed, aileron, elevator and rudder

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Outline

6 Conclusions and Recommendations

Conclusion and RecommendationsConclusions

High L/D ratio is achievable.

Significant reduction in induced drag.

Height (vertical separation) and span ratio has a direct influence on

the overall efficiency.

Recommendations

Appropriate airfoil should be selected.

Design optimization should be coupled with CFD studies.

CFD studies should include viscous effects.

Coupled aerodynamics, stability and structural analyses should be

conducted.27/28

THANK YOU

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