On the Setup of a Test Bench for Predicting Laminar-to-Turbulent Transition on a Flat Plate

Abstract

At turbomachinery relevant flow conditions the boundary layers are often transitional with laminar-to-turbulent transition occurring. The characteristics of the main flow can depend highly on the state of the boundary layer. Therefore it can be vitally important for the designer to understand the process of laminar-to-turbulent transition and to determine the position and length of the transitional region. In this paper the flow over a flat plate is experimentally studied in order to investigate and better understand transitional flow. Preston tube measurements as well as a thermographic camera system were performed for two different inlet velocities in order to determine the position of the transitional zone. The results of the experiment are compared to numerical flow solutions using a common transition model to determine its capability. The simulation has been performed with the two commercial codes CFX ® and Fluent ® by Ansys ® and an in-house code called LINARS. As a result of this study, a better understanding of the experimental and numerical methods for determining transition shall be given.