Freestream Disturbances Characterization in Ludwieg Tubes at Mach 6


The present study aims at freestream disturbances characterization for two hypersonic sister facilities; HLB of the TU Braunschweig and HHK-6 of the USAF Academy. The freestream disturbances are characterized by using a so-called combined modal analysis. For this analysis, measurements are taken by means of hotwire and stagnation point probes. Although both facilities utilize the same nozzle geometry, they have different storage tubes. The present results provide insight into current methods used to characterize freestream disturbances in hypersonic flow. Further assessment is possible by comparisons with recent data from direct numerical simulation of the noise radiated from the hypersonic turbulent boundary layer of the wind tunnel nozzle.

Meeting Name

AIAA Scitech Forum, 2019 (2019: Jan. 7-11, San Diego, CA)


Mechanical and Aerospace Engineering


This work was performed as a part of coordinated research by the AVT-240 group of Science and Technology Organization, STO. The authors want to thank the European Office of Aerospace Research and Development (EOARD) and the Air Force Office of Scientific Research (AFOSR), for providing the financial support.

Keywords and Phrases

Aviation; Boundary layer flow; Digital storage; Hypersonic flow; Modal analysis; Nozzles; Wind tunnels, Free-stream; Hotwire; Ludwieg tube; Nozzle geometries; Stagnation points; Turbulent boundary layers, Hypersonic boundary layers

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2019 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

01 Jan 2019