Transition on a Wing with Spanwise Varying Crossflow Evaluated with Linear Stability Theory

Abstract

The windtunnel model of a wing for spanwise varying crossflow is designed as a testcase for validating transition prediction methods. The wing with a sickle-shaped planform is manufactured out of fibre reinforced plastics. It is equipped with pressure taps and a special layup to increase the contrast of infrared transition measurements. The wing is designed to create three-dimensional boundary layers with increasing crossflow towards the wing tip. Because of the sickle-shaped planform with distinct kinks, spanwise gradients are present and the assumptions of linear local stability theory are therefore challenged. It is found that at locations of high spanwise gradients the transition location moves upstream, due to strong amplification of stationary crossflow vortices. The experimental results are evaluated with linear local stability theory.