Experimental study of shock wave patterns over an airfoil

Abstract

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.In spite of occurring during a short period of time, the transonic regime plays an important role in the flight envelope of an aerospace vehicle, given that complex flow phenomena take place at this speed range, as for example shock wave occurrences and associated shock waveboundary layer interactions (SBLIs). The present study is aimed at investigating the shock wave formation patterns over a NACA 0012 airfoil in the transonic regime as the Mach number and the angle of attack is varied. The angles of attack, α, of 0°, 2°, 4° and 5° were considered, and the Mach number, M, was varied between 0.2 and 0.8. In all tested conditions, measurements were conducted for very small variations of Mach number in the range close to shock wave occurrence, in order to study the shock wave patterns in this region and also to get insights on shockwave-boundary layer interactions (SBLIs) taking place. Significant differences both between laminar and turbulent shockwave formation patterns and fullydeveloped shock structures were detected, as well as Cpvariations due to laminar-turbulent transition.