Experimental Investigation on the Effect of Multi-Winglets

An extensive experimental study is conducted to examine the potentiality of Multi-Winglets (similar to bird tip feathers) for the reduction of Induced Drag, improved CL without increase in span of aircraft wing. The model composed of a rectangular wing built from NACA 0015 airfoil constituted of three winglets, which are small wings without sweep & twist. The test conducted in subsonic wind tunnel at flow speed 20m/s and placing the wing at angle of attack ranging from -5 to +15 deg. And also the wing with no winglet (bare wing) and with single winglet also tested in the same condition as in the case of three winglets (multi-winglet). Wind tunnel balances provided lift measurements and tuft flow visualization obtained wingtip vortex information. The results show that multi-winglet system reduced induced drag by 27.9% and improved CL by 26.5% compare to bare wing

Effect of Micro-Vortex Generator in Hypersonic Inlet

In the present study computational tests were carried out to get an understanding of the flow field in a pure mixedcompression hypersonic inlet at a free stream Mach number of 7 and an altitude of 35km. Structured meshes have been used for depicting the motion of fluid inside the inlet. First, a grid has been selected after conducting a grid study. Two dimensional simulations were carried out with standard sst k-ω model using FLUENT. Computational results are compared with the available data. The results obtained from the computational tests revealed several important flow field details at hypersonic speeds. The basic shock structure inside the inlet was obtained. The boundary layer formed inner side of the engine had an adverse pressure gradient on the top ramp. Due to this the boundary layer thickens and the static pressure starts to decrease whose effect leads till the trailing edge of inlet. By providing small wedge shaped Micro-Vortex Generator (MVG) where the shockboundary layer occurs we can smooth the boundary layer formed inside the inlet. Thus there will be more efficient compression than the actual case. The results obtained in the present series of tests, could help the hypersonic inlet design optimization at offdesign conditio