17 Jun 2016 - F. Nicolosi et alii. 2. Usually investigated in the last phase of aircraft design and testing. Aerodynamic design guidelines of an aircraft dorsal fin.
Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses F. Nicolosi , D. Ciliberti, P. Della Vecchia, and S. Corcione
Dept. of Industrial Engineering, Design of Aircraft and Flight technologies (DAF) Research Group University of Naples “Federico II”, Naples, 80125, Italy
Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Introduction – The dorsal fin
Usually investigated in the last phase of aircraft design and testing
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Introduction – The rudder lock
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Some experimental data about dorsal fin
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Phenomenology Secondary vortex Primary vortex
No dorsal fin
Re = 1.36E6, β = 22° 17/06/2016
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Reference geometry for investigation
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
A preliminary numerical investigation
The quantity of interest is the yawing moment coefficient
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CN
N 1 V 2 Sb 2 F. Nicolosi et alii
Re = 1.36E6, M = 0
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
A parametric investigation
The aircraft geometry is a modular model representative of the regional turboprop airplane category, deeply investigated in recent analyses about directional stability 17/06/2016
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Wind tunnel modular aircraft model The external shape is the same of the CFD model. In practice, physical constraints must be accounted for. Main dimensions: 2.0 m fuselage length 1.5 m wing span 0.5 m horizontal tail span 0.4 m max vertical tail span
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Effects of the dorsal fin on the vertical tail
Vertical tail contribution in different configs. Re = 1.36E6, M = 0 17/06/2016
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Vertical tail and dorsal fin contributions in different configs. Re = 1.36E6, M = 0 10
Pressure coefficient distribution BV config. at β = 15°
BVD config. at β = 19°
CFD 17/06/2016
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Re = 430000 11
Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Aerodynamic interference on the fuselage The aerodynamic interference in the linear range reduces the fuselage directional instability
Effect of the aerodynamic interference due to vertical tail and dorsal fin Effect of the aerodynamic interference due to vertical tail Fuselage alone Fuselage contribution in different configurations. Re = 1.36E6, M = 0 17/06/2016
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Parametric investigation about dorsal fin height hdf hv
Re = 1.36E6, M = 0 Dorsal fin length is kept constant. This geometric parameter seems to be the most important.
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Vertical tail and dorsal fin contributions hdf hv
hdf hv
Vertical tail contribution in different configs. Re = 1.36E6, M = 0 17/06/2016
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Dorsal fin contribution in different configs. Re = 1.36E6, M = 0 14
Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Parametric investigation about dorsal fin length
Re = 1.36E6, M = 0 Dorsal fin height is kept constant. It seems to have little effect on total yawing moment coefficient.
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Parametric investigation about dorsal fin sweep angle
Re = 1.36E6, M = 0 Dorsal fin area is kept constant. It is seems sufficient to avoid sweep angles less than 50° to get the desired effects.
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
Parametric investigation about dorsal fin area
Re = 1.36E6, M = 0 Dorsal fin sweep angle is kept constant. By reducing the fin area, additional weight and drag are reduced.
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Aerodynamic design guidelines of an aircraft dorsal fin through numerical and experimental analyses
A numerical investigation about additional aerodynamic drag Semi-empirical approach CD 0
4 t t Sdf , wet 1.03 2 60 2.58 c c Sw log Re
0.455
ΔCD0 includes both friction and pressure drag contributions calculated with and without dorsal fin
