TY - GEN
T1 - Direct numerical simulations of nonlinear entropy-layer instability waves
AU - Meersman, John A.
AU - Hader, Christoph
AU - Fasel, Hermann F.
N1 - Funding Information:
This work was supported by ONR Grant N000141712338, with Dr. Eric Marineau serving as the program manager. Computer time was provided by the U.S. Army Engineering Research and Development Center (ERDC) under the Department of Defense (DOD) High Performance Computing Modernization Program (HPCMP) ONRDC42942526. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research or the U.S. Government. The authors would like to thank Anthony Haas, Andrew Hartman, and Dr. Stefan Wernz for many productive discussions.
Publisher Copyright:
© 2021, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2021
Y1 - 2021
N2 - Direct Numerical Simulations (DNS) were carried out for a blunted straight cone geometry at Mach 6 in order to investigate the nonlinear stages of the transition process initiated by disturbances in the entropy layer. The flow conditions of the Boeing/AFOSR Mach 6 Quiet Tunnel (BAM6QT) at Purdue University were used for the numerical investigations. In the simulations, “controlled” disturbances were introduced locally into the entropy layer by volume forcing of the energy equation. Low amplitude (linear) DNS revealed an unstable region that was not found using conventional Linear Stability Theory (LST), which only found a weak entropy mode instability for two-dimensional waves. A highly-resolved oblique breakdown DNS has shown that transition can be initiated by forcing large amplitude, oblique disturbances in the entropy layer. Streamwise “hot” streaks were observed in Stanton number contours on the surface of the cone. The streak spacing in the azimuthal direction corresponds to the azimuthal wavenumber of the steady streamwise mode that is nonlinearly generated by the forced oblique waves.
AB - Direct Numerical Simulations (DNS) were carried out for a blunted straight cone geometry at Mach 6 in order to investigate the nonlinear stages of the transition process initiated by disturbances in the entropy layer. The flow conditions of the Boeing/AFOSR Mach 6 Quiet Tunnel (BAM6QT) at Purdue University were used for the numerical investigations. In the simulations, “controlled” disturbances were introduced locally into the entropy layer by volume forcing of the energy equation. Low amplitude (linear) DNS revealed an unstable region that was not found using conventional Linear Stability Theory (LST), which only found a weak entropy mode instability for two-dimensional waves. A highly-resolved oblique breakdown DNS has shown that transition can be initiated by forcing large amplitude, oblique disturbances in the entropy layer. Streamwise “hot” streaks were observed in Stanton number contours on the surface of the cone. The streak spacing in the azimuthal direction corresponds to the azimuthal wavenumber of the steady streamwise mode that is nonlinearly generated by the forced oblique waves.
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M3 - Conference contribution
AN - SCOPUS:85100117487
SN - 9781624106095
T3 - AIAA Scitech 2021 Forum
SP - 1
EP - 16
BT - AIAA Scitech 2021 Forum
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2021
Y2 - 11 January 2021 through 15 January 2021
ER -