Introduction Aerodynamic Performance Analysis of A Non Planar C Wing using Experimental and Numerical Tools Mano Prakash R., Manoj Kumar B., Lakshmi Narayanan Applied Aerodynamics Conference Modelling & Simulation In The Aerodynamic Design Process BRISTOL / 17 - 19 JULY 2012

Outline Introduction Computational Fluid Dynamics Wind tunnel Testing 1 Introduction 2 Computational Fluid Dynamics 3 Wind tunnel Testing 4 Induced drag comparison 5 Radio – Controlled model 6 Conclusions and Recommendations

Outline 1 Introduction

Thrust required curve for jet aircraft 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 aircraft

Introduction 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.

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 view

Outline 2 Computational Fluid Dynamics

CFD 3D 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.

Initial Geometry Model 1 Selection Criteria: Reference wing dimensions - Span = 500mm, Chord = 150mm, Aspect Ratio = 3.33

Surface grids Coarse Medium Fine Elements: 5626709 8757321 12782950

Grids -Cut Section at 50% of span Coarse Medium Fine Growth rate 1.2 1.1 1.05

Flow Field Conditions Reynolds 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

CFD Results Force convergence M∞ = 0.1, Re∞ = 3 × 105, α = 5o Force coefficients do not asymptote on fine grid.

Final model Lift / Drag Vs. Angle of attack 𝐿 𝐷 α

Outline 3 Wind tunnel Testing

Wind tunnel Subsonic wind tunnel Hindustan College Of Engineering, Anna University, Chennai, India. Tunnel type : Open loop tunnel Test section : 60cm × 60cm × 200cm Velocity range: 0 – 80m/s

Experimental set up Model Material used: Fiberglass Total pressure taps: 32 Manufacturing accuracy: ± 0.00012mm

Results   𝐿 𝐷 𝐿 𝐷 α α

Outline 4 Induced drag comparison

Planar wing  

C-wing  

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

Comparison curve 𝑪𝑫𝑰 α

Outline 5 Radio – Controlled model

Model Materials: Fuselage - Spad board reinforced with balsa wood. Wing and tail plane - Coroplast reinforced with balsa wood. Controls: Speed, aileron, elevator and rudder

Outline 6 Conclusions and Recommendations

Conclusion and Recommendations Conclusions 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.

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