Title

Direct Numerical Simulation of Hypersonic Turbulent Boundary Layer Inside an Axisymmetric Nozzle

Abstract

As a first step toward a study of acoustic disturbance field within a conventional, hypersonic wind tunnel, direct numerical simulations (DNS) of a Mach 6 turbulent boundary layer on the inner wall of a straight axisymmetric nozzle are conducted and the results are compared with those for a at plate. The DNS results for a nozzle radius to boundary-layer thickness ratio of 5:5 show that the turbulence statistics of the nozzle-wall boundary layer are nearly unaffected by the transverse curvature of the nozzle wall. Before the acoustic waves emanating from different parts of the nozzle surface can interfere with each other and undergo reflections from adjacent portions of the nozzle surface, the rms pressure fluctuation beyond the boundary layer edge increases toward the nozzle axis, apparently due to a focusing effect inside the axisymmetric configuration. Spectral analysis of pressure fluctuations at both the wall and the freestream indicates a similar distribution of energy content for both the nozzle and the at plate, with the peak of the premultiplied frequency spectrum at a frequency of ωδ/U ≈ 6:0 inside the free stream and at ωδ/U ≈ 2:0 along the wall. The present results provide the basis for follow-on simulations involving reverberation effects inside the nozzle.

Meeting Name

55th AIAA Aerospace Sciences Meeting, AIAA SciTech Forum (2017: Jan. 9-13, Grapevine, TX)

Department(s)

Mechanical and Aerospace Engineering

Comments

This material is based on the work supported by the Air Force Office of Scientific Research under award number FA9550-14-1-0170, managed by Dr. Ivett Leyva.

Keywords and Phrases

Boundary layers; Hypersonic boundary layers; Mach number

International Standard Book Number (ISBN)

978-162410447-3

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Share

 
COinS