Investigation of Surface Flow Behaviors on Wing Model Made of Different Airfoils

Abstract

This article is focused on the flow behavior observed using the surface oil visualization method on a wing model consisting of four airfoils. In this way, it is aimed to contribute to the insufficient number of literature studies in which flow behaviors are examined by visualization in the wing model consisting of different profiles. The flow behaviors on the surface of the wing and the surface of airfoils forming the wing are presented at three different Reynolds numbers (2x105, 3x105 and 4x105) and a range of distinct attack angles ranging from 0 to 40 degrees. The tests were applied in a low-speed wind tunnel. After the surface imaging experiments, separation point, reattachment point, and bubble length values reflecting flow behavior were measured for the wing and each airfoils. The flow on surface was trying to transition from laminar to turbulent at angles of attack between 0-16 degrees and the turbulent flow attempted to spread or reattach over the entire surface at between 24-40 degrees. Increasing of the angle of attack and Reynolds number led to reducing the x/c values numerically, weakening the surface separation bubble, and inducing it to shift towards the leading edge. In terms of x/c value, the wing model generally follows a trend close to airfoil B at 0 and 8 degrees and close to airfoil A at 16 degrees. Additionally, the flow behaviors on the wing model are similar to airfoils A and B in terms of the flow phenomena.