2016 article

Streamwise Oscillation of Airfoils into Reverse Flow

Granlund, K. O., Ol, M. V., & Jones, A. R. (2016, May). AIAA JOURNAL, Vol. 54, pp. 1628–1636.

By: K. Granlund n, M. Ol* & A. Jones*

co-author countries: United States of America 🇺🇸
Source: Web Of Science
Added: August 6, 2018

A NACA 0012 airfoil is oscillated in streamwise direction in a constant freestream and at a fixed incidence angle such that reverse flow occurs cyclically. Force measurements reveal that lift is close to unsteady theory while advancing into the freestream, if the angle of attack permits attached flow. Lift is augmented at large angles of attack, where the flow is separated under steady conditions, and does not become appreciatively negative in flow reversal for either attached or separated flow, contrary to one unsteady theory but supported by another. Dye flow visualization reveals a coherent vortical structure upstream of the leading edge before flow reversal, which is believed to attenuate negative lift.