The Role of the Low-Speed Wind Tunnel in Transition Research

Abstract

We need to understand much more about the physical processes that take place during the transition from laminar to turbulent flow if we are going to be in a stronger position to predict the event. The aim of much of the present transition research is directed to the prediction of transition on the wings of modern transonic aircraft. It is therefore desirable to consider the stability of the types of boundary layers that arise on real swept wings in compressible flow. Such problems are complicated and are therefore difficult to study, especially through experiment. It is much easier to investigate the various phases of the transition process at low speed. I do not believe that the physics are greatly different at low speed and so we have the opportunity of experimentally investigating some of the fundamental aspects of the process without the added complexity of working in a high-speed tunnel. The low-speed wind tunnel has a vital role to play in such research. Not only is it much easier to do the work in a low-speed tunnel, but in general turbulence levels are lower and the costs of operating the facilities are much less.