The effects of changing the canard trailing-edge inspired by morphing surfaces on a diamond wing flow at low angles of attack

Abstract

This article investigates experimentally and numerically the effects of altering the canard cross-sectional area on a diamond wing flow field pattern. For this purpose, the trailing-edge of the canard with the NACA 0012 airfoil section is statically angled. The angle modification created is inspired by morphing surfaces seamlessly. The leading-edge sweep-back angle of the investigated diamond wing was 50 degrees, and its chord and span lengths were 175 and 234 mm, respectively. The flow characteristics were comprehensively analyzed at angles of attack of 5 and 10 degrees for a free stream velocity of 12/5 m/s, equivalent to Re = 2.16 × 10 5 . A one-dimensional hot-wire anemometry is employed to investigate the flow pattern, including measurements of axial turbulence intensity, velocity measurements, and frequency analysis. Additionally, a multi-probe setup is utilized to examine the pressure coefficient for various wing cross-sections and the normal velocity component. The vorticity field, Q- criteria, surface pressure, coefficient of lift, and pitching-moment are numerically carried out using the Ansys- Fluent software. The results revealed that a low-pressure region forms in the base model, characterized by a less lateral extent compared to the modified models. The downward deflection of the canard reduces the distance between the vortices, thereby significantly increasing vortex interaction, particularly at lower angles of attack. At an angle of attack of α α =5 ∘ =5 ∘ , the lift coefficient (C L ) of the downward-morphed canard increased by 43 % and 85 % relative to the base model and the upward-morphed configuration, respectively. Increasing the angle of attack beyond , led to an enhancement in suction and an enlargement of both the leading-edge vortex (LEV) and the canard-generated vortex for all examined span-wise sections. At α = 10 ∘ , the secondary vortex structure exhibited a notable variation in the vortical flow pattern. Among all investigated models, the highest and lowest lift coefficients (C L ) of the full-body models were associated with the downward-morphed and upward-morphed canard models, respectively.