Receptivity of a high-speed boundary layer to temperature spottiness

Федоров, А. В.; Рыжов, А. А.; Soudakov, Vitaly; Utyuzhnikov, Sergey

doi:10.1017/jfm.2013.111

Cited by 39 publications

(14 citation statements)

References 38 publications

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“…This is similar to the synchronism with vorticity/entropy waves that occurs when the branch cut at c r = 1 is crossed (Fedorov & Khokhlov 2001;Fedorov et al 2013), which has been found to produce increased receptivity to vorticity and entropy spottiness. The synchronism identified here is expected to cause a similar effect, but with enhanced receptivity to acoustic disturbances in the free stream rather than vorticity/entropy disturbances.…”

Section: Shape Of Dispersion Curvesupporting

confidence: 67%

Stability of highly cooled hypervelocity boundary layers

2015

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The influence of high levels of wall cooling on the stability of hypervelocity boundary layers is investigated. Such conditions are relevant to experiments in high-enthalpy impulse facilities, where the wall temperature is much smaller than the free-stream temperature, as well as to some real flight scenarios. Some effects of wall cooling are well known, for instance, the stabilization of the first mode and destabilization of the second mode. In this paper, several new instability phenomena are investigated that arise only for high Mach numbers and high levels of wall cooling. In particular, certain unstable modes can travel supersonically with respect to the free stream, which changes the nature of the dispersion curve and leads to instability over a much wider band of frequencies. The cause of this phenomenon, the range of parameters for which it occurs and its implications for boundary layer stability are examined. Additionally, growth rates are systematically reported for a wide range of conditions relevant to high-enthalpy impulse facilities, and the stability trends in terms of Mach number and wall temperature are mapped out. Thermal non-equilibrium is included in the analysis and its influence on the stability characteristics of flows in impulse facilities is assessed.

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Section: Shape Of Dispersion Curvesupporting

confidence: 67%

Stability of highly cooled hypervelocity boundary layers

2015

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“…Research on the receptivity problem has received increasing attention due to its practical importance. The various types of the external disturbances include freestream turbulence (FST) [11][12][13][14], surface roughness [15], solid particulates [16], wall vibrations [17], etc. Recent reviews can be found in Fedorov [18] and Zhong and Wang [19].…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned earlier, recent work on the receptivity problem include the receptivity to various disturbances, e.g., temperature spottiness [14], solid particulates [16] and surface roughness [39] but mainly concentrating on the the behavior of the Mack mode. The receptivity of Görtler vortices in hypersonic boundary layers received relatively little attention apart from the work of Whang and Zhong [40,41] who made the investigation on the steady Görtler vortices.…”

Section: Introductionmentioning

confidence: 99%

Study of the Discrete Spectrum in a Mach 4.5 Görtler Flow

Ren

2014

Flow Turbulence Combust

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Evolution of the discrete spectrum in the Ma = 4.5 boundary layer is studied with LST and PSE approaches. Both two-dimensional (2-D) and three-dimensional (3-D) disturbances are considered with streamwise curvature effects. The concave curvature shows a destabilizing effect on the 2-D second/third mode when the fast mode (mode F (1) , mode F (2) ...) synchronizes with the slow mode (mode S). The spectrum branching in the synchronization between the mode F (2) and mode S is also observed. The increase in the spanwise wavenumber(3-D disturbances), on the other hand, suppresses the synchronization between mode F and mode S and reduces the growth rate of the unstable mode. With regard to the 3-D disturbances subjecting to the concave curvature, the mode S originating from the slow acoustic wave amounts to the unsteady Görtler mode while the quasi-steady Görtler mode emanates from the continuous spectrum of the vorticity/entropy wave.

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“…Fedorov et al [19,20] performed a numerical simulation of temporally sinusoidal temperature spots over a flat plate in a Mach 6 flow. They computed a case with the temperature spots initially imposed at a short distance above the boundary layer in the flowfield behind the oblique shock and another case with the temperature spots initially imposed in front of the shock at a short distance above the level of the plate.…”

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confidence: 99%

Numerical Study of Hypersonic Boundary-Layer Receptivity with Freestream Hotspot Perturbations

Huang

Zhong

2014

AIAA Journal

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This paper presents a numerical-simulation study of transient flow over a blunt compression cone under the effect of freestream hotspot perturbations. This study is motivated by concurrent wind-tunnel laser-spot experiments carried out at Purdue University. The flow conditions used in the simulation are based on the experimental conditions. The simulation is performed using a high-order shock-fitting finite-difference scheme. The simulation results show that the hotspot is able to excite second-mode instability, where the instability growth is found to be dominant in the boundary layer. The receptivity mechanism is investigated by comparing the simulated results with linear-stability theory. Fast acoustic waves generated by hotspot-shock interaction excite the boundary-layer disturbances. Also, the synchronization of mode F and mode S leads to the dominance of boundary-layer disturbances by the growing second mode. Nomenclature a = phase speed c v = specific heat in a constant-volume process d = perturbation of a variable e = total energy per unit volume F = frequency F j = inviscid flux vector in jth direction F vj = viscous flux vector in jth direction H = local height from the wall L = length scale of the boundary-layer thickness M ∞ = freestream Mach number P = pressure P ∞ = freestream pressure Pr = Prandtl number q j = heat flux due to thermal conduction R = local Reynolds number R = gas constant Re ∞ = freestream Reynolds number per unit length S = entropy S ∞ = freestream entropy s = natural coordinate along the body surface T = temperature T o = total temperature T r = reference temperature T s = Sutherland's temperature T wall = temperature at wall T ∞ = freestream temperature t = time u 1 , u 2 , u 3 = velocity components u ∞ = freestream velocity y n = normalized local normal distance from the wall α = streamwise complex wave number α i = local growth rate α r = local wave number γ = ratio of specific heat ζ = coordinate in azimuthal direction η = coordinate in the direction normal to the wall κ = heat conductivity coefficient μ = viscosity coefficient μ ∞ = freestream viscosity coefficient μ r = reference viscosity coefficient ξ = coordinate in streamwise direction ρ = mass density ρ ∞ = freestream density τ = time in computational domain τ ij = shear-stress tensor φ = phase angle ω = circular frequency Superscripts = dimensional variable 0 = perturbation of a variable

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Receptivity of a high-speed boundary layer to temperature spottiness

Cited by 39 publications

References 38 publications

Stability of highly cooled hypervelocity boundary layers

Stability of highly cooled hypervelocity boundary layers

Study of the Discrete Spectrum in a Mach 4.5 Görtler Flow

Numerical Study of Hypersonic Boundary-Layer Receptivity with Freestream Hotspot Perturbations

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