Proceedings of the
International Conference on Mechanical Engineering 2009
(ICME2009) 26- 28 December 2009, Dhaka, Bangladesh
 

ICME09-FM-10

INDUCED DRAG REDUCTION FOR MODERN AIRCRAFT
WITHOUT INCREASING THE SPAN OF THE WING BY USING
WINGLET

Mohammad Mashud, Md. Hasan Ali, Abdullah-Al-Nahian and S. M. S. Selim
Department of Mechanical Engineering
Khulna University of Engineering & Technology, Khulna

ABSTRACT

This paper describes the potential of winglets for the reduction of induced drag without increasing the span of the aircraft. For this experiment a model aircraft has been constructed by aluminum-alloy whose wings profile is NACA 4315. There are three different types (rectangular, triangular and circular) of winglet are constructed for experiment. Aerodynamic characteristics for the model aircraft wing with rectangular, triangular and circular winglets and without winglet have been studied using a subsonic wind tunnel of 36cm×36cm rectangular test section. Drag measurements are carried out using an external balance. Tests are carried out on the aircraft model with and without winglet at the Reynolds numbers 0.16×106, 0.18×106, 0.20×106, 0.23×106 and 0.25×106. The experimental results show that the drag decreases by 26.4% - 30.9% as compared to the aircraft model with and without winglet for the maximum Reynolds number considered in the present study.

 

Keywords: Induced Drag, Wing, Winglet, Aircraft and Aerodynamics.

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 Proceedings of the

International Conference on Mechanical Engineering 2009
(ICME2009) 26- 28 December 2009, Dhaka, Bangladesh
ICME09-FM-09

A COMPUTATIONAL STUDY OF TRANSONIC MOIST AIR FLOW
AROUND A SYMMETRIC DISK BUTTERFLY VALVE

A. B. M. Toufique Hasan1, Mohammad Mamun2, Shigeru Matsuo3 and Toshiaki Setoguchi4
1 Graduate School of Science and Engineering, Saga University, Saga, Japan
2 Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka ,
Bangladesh
3Department of Mechanical Engineering, Saga University, Saga, Japan
4 Institute of Ocean Energy, Saga University, Saga, Japan

ABSTRACT

Transonic flow around a symmetric disk butterfly valve is associated with the appearance of shock waves standing on valve surfaces. In this case, the interaction between shock wave and boundary layer becomes complex and thus generates the flow induced aerodynamic instability. In the transonic or supersonic flow where vapour is contained in the main flow, the rapid expansion of the flow may give rise to non-equilibrium condensation. In the present study, the effect of non-equilibrium condensation of moist air on the shock induced flow field oscillation around a butterfly valve was investigated numerically. The results showed that in case with non-equilibrium condensation, the flow field aerodynamic instabilities such as root mean square of pressure oscillation and shock induced oscillation frequency are reduced significantly compared with those without the non-equilibrium condensation. Moreover, the total pressure loss increases and the vortex shedding frequency is reduced with non-equilibrium condensat

Keywords: Transonic Flow, Shock Induced Oscillation, Moist Air.

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