It is known that wings having a low aspect ratio are more suitable for sports and pleasure vehicles, while those having a large aspect ratio are better suited for transport purposes. However, for the specific application of train, it is not possible to have large wing span. Tandem wings (one wing in the wake of the other) may be regarded as a solution for this problem. It is found that use of tandem wings for WIG vehicle (WIG: Wing-in-Ground-effect) helps in getting better lift/drag characteristics and also in providing the necessary longitudinal stability when the angle of attack (alpha) is not large. However, in such a configuration, flow trailing from the front wing will modify the flow pattern over the rear wing and change its aerodynamic characteristics. Little is known about this influence on the performance of the tandem wings. In the present work, a detailed study of a tandem wing configuration in close proximity to ground was carried out. It was found from the experiments that both, the angle of attack and the ground clearance of the wings have a strong influence on the aerodynamic characteristics of the configuration. Higher angle of attack results in higher lift coefficient, but at the same time, drag coefficient is also increased. For smaller spacings between the tandem wings, a larger interference effect between the wake of the front wing and the rear wing was observed. At angles of attack of 2 deg (for both wings), maximum lift to drag ratio was obtained. For small ground clearance of the wings, lower clearance of the side plates resulted in higher values of lift to drag ratio. The system showed high pitching instability for the present case of the static testing.
Experimental investigation on the aerodynamic characteristics fo a tandem wing configuration in close ground proximity
Experimentelle Untersuchung der aerodynamischen Eigenschaften einer Tandemflügel-Konfiguration in enger Bodennähe
JSME International Journal, Series B (Fluids and Thermal Engineering) ; 42 , 4 ; 612-618
1999
7 Seiten, 6 Bilder, 13 Quellen
Article (Journal)
English
Some Aerodynamic Characteristics of A Tandem Wing Configuration in Close Ground Proximity
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