Numerical Anslysis of Cropped Delta Wing with Reflex Camber Cross-Section at Transonic Speed with Leading-Edge Tubercles

Abstract

Most of the modifications in flow control surfaces are bioinspired resulting in enhanced lift and thrust efficiency. In nature, hump back whales have evolved with tubercles at the leading-edge (L.E.) of their flippers. There is a strong evidence from the published literature that leading-edge tubercles (L.E.T.) improve stall characteristics of various lifting surfaces. L.E.T. are also known to reduce flow in the span-wise direction. The reduction in size and vorticity of the wingtip vortices is also a known benefit of adding tubercles at the L.E. of lifting surfaces. In this paper, the effects of L.E.T. are analyzed on a cropped delta wing having reflex camber cross-section (C.S.) at low angle of attack (A.O.A.) and transonic flight speed. An improved performance of the wing with L.E.T. is indicated by the results from the numerical simulations when compared to the baseline design. The improved characteristics of the modified wing (M.W.) in comparison with the baseline wing (B.W.) can be attributed, partly to the varying span-wise pressure distribution near the L.E. of the M.W. The improved performance of the M.W. can also be credited to the creation of a pair of chord-wise vortices behind the tubercle troughs as well as an improved stall performance and reduction in both the strength of wingtip vortices and span-wise flow.