Record Details

Secondary Instability of Stationary Crossflow Vortices in Mach 6 Boundary Layer Over a Circular Cone
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Author and Affiliation:
Li, Fei(NASA Langley Research Center, Hampton, VA, United States);
Choudhari, Meelan M.(NASA Langley Research Center, Hampton, VA, United States);
Paredes-Gonzalez, Pedro(NASA Langley Research Center, Hampton, VA, United States);
Duan, Lian(Missouri Univ. of Science and Technology, Rolla, MO, United States)
Abstract: Hypersonic boundary layer flows over a circular cone at moderate incidence can support strong crossflow instability. Due to more efficient excitation of stationary crossflow vortices by surface roughness, such boundary layer flows may transition to turbulence via rapid amplification of the high-frequency secondary instabilities of finite amplitude stationary crossflow vortices. The amplification characteristics of these secondary instabilities are investigated for crossflow vortices generated by an azimuthally periodic array of roughness elements over a 7-degree half-angle circular cone in a Mach 6 free stream. Depending on the local amplitude of the stationary crossflow mode, the most unstable secondary disturbances either originate from the second (i.e., Mack) mode instabilities of the unperturbed boundary layer or correspond to genuine secondary instabilities that reduce to stable disturbances at sufficiently small amplitudes of the stationary crossflow vortex. The predicted frequencies of dominant secondary disturbances are similar to those measured during wind tunnel experiments at Purdue University and the Technical University of Braunschweig, Germany.
Publication Date: Dec 01, 2015
Document ID:
20160002215
(Acquired Feb 25, 2016)
Subject Category: AERONAUTICS (GENERAL)
Report/Patent Number: NASA/TM-2015-218997, L-20650, NF1676L-23272
Document Type: Technical Report
Contract/Grant/Task Num: WBS 109492.02.07.01.01
Financial Sponsor: NASA Langley Research Center; Hampton, VA, United States
Organization Source: NASA Langley Research Center; Hampton, VA, United States
Description: 29p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution as joint owner in the copyright
NASA Terms: CROSS FLOW; VORTICES; HYPERSONIC BOUNDARY LAYER; CIRCULAR CONES; BOUNDARY LAYER FLOW; SURFACE ROUGHNESS; STABILITY; MACH NUMBER; WIND TUNNELS; AMPLIFICATION; TURBULENCE
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