Characterization of Freestream Disturbances in Conventional Hypersonic Wind Tunnels

Abstract

While low disturbance ("quiet") hypersonic wind tunnels are believed to provide more reliable extrapolation of boundary layer transition behavior from ground to flight, the presently available quiet facilities are limited to Mach 6, moderate Reynolds numbers, low freestream enthalpy, and subscale models. As a result, only conventional ("noisy") wind tunnels can reproduce both Reynolds numbers and enthalpies of hypersonic flight configurations, and must therefore be used for flight vehicle test and evaluation involving high Mach number, high enthalpy, and larger models. This article outlines the recent progress and achievements in the characterization of tunnel noise that have resulted from the coordinated effort within the AVT-240 specialists group on hypersonic boundary layer transition prediction. New Direct Numerical Simulation (DNS) datasets elucidate the physics of noise generation inside the turbulent nozzle wall boundary layer, characterize the spatiotemporal structure of the freestream noise, and account for the propagation and transfer of the freestream disturbances to a pitot-mounted sensor. The new experimental measurements cover a range of conventional wind tunnels with different sizes and Mach numbers from 6 to 14 and extend the database of freestream fluctuations within the spectral range of boundary layer instability waves over commonly tested models. Prospects for applying the computational and measurement datasets for developing mechanism-based transition prediction models are discussed.

Meeting Name

AIAA Aerospace Sciences Meeting, 2018 (2018: Jan. 8-12, Kissimmee, FL)

Department(s)

Mechanical and Aerospace Engineering

Comments

This work was sponsored by the Air Force Office of Scientific Research (under grants FA9550-14-1-0170, FA9550-17-1-0250, and FA9550-12-1-0167).

Keywords and Phrases

Aerodynamics; Aviation; Boundary layer flow; Enthalpy; Hypersonic boundary layers; Hypersonic flow; Hypersonic vehicles; Mach number; Reynolds number, Boundary layer instability; Boundary layer transitions; High mach number; Hypersonic flights; Hypersonic wind tunnels; Moderate Reynolds numbers; Spatio-temporal structures; Transition prediction, Wind tunnels

International Standard Book Number (ISBN)

978-162410524-1

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

01 Jan 2018

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