Sensitivity of Second-Mode Linear Stability to Constitutive Models within Hypersonic Flow

2005 ◽  
Author(s):  
Ian Lyttle ◽  
Helen Reed
Keyword(s):  
Hypersonic Flow ◽  
Linear Stability ◽  
Constitutive Models ◽  
Second Mode

Linear stability of hypersonic flow in thermochemical nonequilibrium

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 958-964
Author(s):  
Mary L. Hudson ◽  
Ndaona Chokani ◽  
Graham V. Candler
Keyword(s):  
Hypersonic Flow ◽  
Linear Stability

Simulation of Second-Mode Instability in a Real-Gas Hypersonic Flow with Graphite Ablation

AIAA Journal ◽  
2014 ◽  
Vol 52 (8) ◽  
pp. 1632-1652 ◽  
Author(s):  
Clifton H. Mortensen ◽  
Xiaolin Zhong
Keyword(s):  
Hypersonic Flow ◽  
Mode Instability ◽  
Real Gas ◽  
Second Mode

Linear stability of hypersonic flow in thermochemical nonequilibrium

1996 ◽  
Author(s):  
Mary Hudson ◽  
Ndaona Chokani ◽  
Graham Candler
Keyword(s):  
Hypersonic Flow ◽  
Linear Stability

Linear stability of hypersonic flow over a parabolic leading edge

1997 ◽  
Author(s):  
Sean Hu ◽  
Sean Hu ◽  
Xiaolin Zhong ◽  
Xiaolin Zhong
Keyword(s):  
Hypersonic Flow ◽  
Linear Stability ◽  
Leading Edge

Instability and transition mechanisms induced by skewed roughness elements in a high-speed laminar boundary layer

2016 ◽  
Vol 805 ◽  
pp. 262-302 ◽  
Author(s):  
Gordon Groskopf ◽  
Markus J. Kloker
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Linear Stability ◽  
Stability Theory ◽  
High Speed ◽  
Roughness Element ◽  
Linear Stability Theory ◽  
Minor Importance ◽  
Roughness Elements ◽  
Second Mode

The disturbance evolution in a Mach-4.8 zero-pressure-gradient flat-plate boundary-layer flow altered by discrete three-dimensional roughness elements is investigated including a laminar breakdown scenario. Direct numerical simulation (DNS), as well as the biglobal linear stability theory based on two-dimensional eigenfunctions in flow cross-sections, are applied. Roughness elements with high ratios of spanwise width to streamwise length are compared at varying height and skewing angles with respect to the oncoming flow. For an oblique roughness, the element’s height is varied between 27 % and 68 % of the undisturbed boundary-layer thickness. Compared to a symmetric roughness element an obliquely placed element generates a more pronounced low-speed streak in the roughness wake. The linear stability analysis reveals the occurrence of eigenmodes that can be associated with the first and second modes in the flat-plate flow. At identical roughness height, larger amplification is found for the eigenmodes of the oblique set-up. The results are confirmed by unsteady DNS showing very good agreement with stability theory; transient-growth behaviour in the near wake of the roughness is of minor importance. The comparison of the results gained for adiabatic wind-tunnel flow conditions with those for atmospheric-flight conditions with wall cooling reveals significant differences in the wake vortex system with subsequent impact on the stability properties of the flow. The hot-flow cases are less unstable at identical roughness Reynolds numbers. A variation of the wall cooling shows that the roughness-wake first- and second-mode behaviour is similar to that of the flat-plate flow: wall cooling stabilizes the first-mode and destabilizes the second-mode instabilities of the roughness wake.

scholarly journals Instability of g-Mode Oscillations in White Dwarf Stars

1979 ◽  
Vol 53 ◽  
pp. 388-391
Author(s):  
Douglas A. Keeley
Keyword(s):  
Linear Stability ◽  
Growth Rates ◽  
White Dwarf ◽  
Mode Frequency ◽  
Radial Mode ◽  
Mode Instability ◽  
Dwarf Stars ◽  
White Dwarf Stars ◽  
Inner Radius ◽  
Second Mode

A white dwarf model with M=.6 M⊙, Te=12000K, and L=1.2×1031 erg sec-1 provided by A.N. Cox has been tested for linear stability of radial oscillations. The radial mode instability first reported for this model by Cox, et. al (1979) has been confirmed. The growth rates obtained are comparable to the rates found by Cox. A sequence of ℓ=2 g-modes has also been found to be unstable. The e-folding times range from around 1011 periods for a 137 second mode (1 radial node) to less than 100 periods for a 629 second mode (17 nodes). It is likely that the latter rate is too high because the eigenfunction has been forced to vanish at the non-zero inner radius of the model, at which the Brunt-Väisäla frequency is barely less than the mode frequency.

Instability of hypersonic flow over a cone

1997 ◽  
Vol 345 ◽  
pp. 383-411 ◽  
Author(s):  
SHARON O. SEDDOUGUI ◽  
ANDREW P. BASSOM
Keyword(s):  
Stability Analysis ◽  
Hypersonic Flow ◽  
Linear Stability ◽  
Weak Interaction ◽  
Linear Stability Analysis ◽  
Interaction Region ◽  
The Stability ◽  
Axisymmetric Disturbances

The linear stability analysis of hypersonic flow over a sharp slender cone with an attached shock is described. Attention is focused on the viscous modes of instability which may be described by a triple-deck structure. The situation in which both the effect of the shock and the influence of curvature are important is considered in the weak-interaction region. Both neutral and non-neutral solutions are presented for both axisymmetric and non-axisymmetric disturbances. The results obtained suggest that the effect of curvature on the stability of hypersonic flow is significant when the attached shock is taken into account.

Linear Stability of Hypersonic Flow in Thermochemical Nonequilibrium

AIAA Journal ◽  
10.2514/2.204 ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 958-964 ◽  
Author(s):  
Mary L. Hudson ◽  
Ndaona Chokani ◽  
Graham V. Candler
Keyword(s):  
Hypersonic Flow ◽  
Linear Stability
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