Numerical Simulations of Hypersonic Boundary-Layer Instability with Wall Blowing

Ghaffari, Shirin; Marxen, Olaf; Iaccarino, Gianluca; Shaqfeh, Eric S. G.

doi:10.2514/6.2010-706

Cited by 17 publications

(12 citation statements)

References 8 publications

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“…Fluids 25, 104107 (2013) basic state for a flat plate boundary layer, 11,12 wherein blowing was shown to have a destabilizing effect on boundary layer instabilities. This paper is focused on the transition mechanisms due to the effects of out-gassing in the absence of surface roughness.…”

Section: -2mentioning

confidence: 99%

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Effects of injection on the instability of boundary layers over hypersonic configurations

Choudhari

Chang

et al. 2013

Physics of Fluids

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A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects Phys. Fluids 23, 084108 (2011); 10.1063/1.3614526Direct numerical simulation of breakdown to turbulence in a Mach 6 boundary layer over a porous surface Phys. Fluids 22, 094105 (2010);Computations are performed to study the boundary layer instability mechanisms pertaining to hypersonic vehicles with significant ablative effects. The process of laminar-turbulent transition over vehicles with ablative heat shields can be influenced by both the out-gassing associated with surface pyrolysis and the resulting modification of surface geometry including the formation of micro-roughness. To isolate the effects of out-gassing, this paper examines the stability of canonical boundary layer flows over smooth surfaces in the presence of gas injection into the boundary layer, with an emphasis on the case of massive injection that is relevant to previous laboratory experiments. For a slender cone, the effects of strong out-gassing on the predominantly second mode instability are found to be weakly stabilizing. This new, somewhat surprising result is confirmed by computations carried out on a flat plate boundary layer at high Mach numbers. In contrast, for a blunt capsule flow dominated by first mode instability, the effect of out-gassing is shown to be strongly destabilizing, consistent with the well-known behavior of subsonic boundary layers. C 2013 AIP Publishing LLC. [http://dx.

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Section: -2mentioning

confidence: 99%

“…This paper is focused on the transition mechanisms due to the effects of out-gassing in the absence of surface roughness. Previous studies related to the effects of blowing on flat plate boundary layers 11,12 are extended first to a slender cone and then to a blunt capsule. Results for each of these geometries are presented in Secs.…”

Section: -2mentioning

confidence: 99%

Effects of injection on the instability of boundary layers over hypersonic configurations

Choudhari

Chang

et al. 2013

Physics of Fluids

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“…Johnson et al 19 used linear stability analysis to analyze non-reacting and reacting hypersonic boundary layer stability with blowing and suction. Ghaffari et al 20 performed a linear stability analysis of a hypersonic perfect gas flat plate boundary layer with wall blowing and found that as blowing increases the maximum amplification rate of the disturbance instability grows and moves to lower frequencies. Li et al 21 studied boundary layer instability mechanisms for hypersonic perfect gas flows over slender cones and blunt capsules at zero angle of attack and an angle of attack of 16 o .…”

Section: Introductionmentioning

confidence: 99%

High-Order Shock-Fitting Method for Hypersonic Flow with Graphite Ablation and Boundary Layer Stability

Mortensen

Zhong

2012

42nd AIAA Fluid Dynamics Conference and Exhibit

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A high-order shock-fitting method with thermochemcial nonequilibrium and finite rate boundary conditions for graphite ablation is presented. The method is suitable for direct numerical simulation of boundary layer stability with graphite ablation. Validation with three computational data sets and one set of experimental data is shown. Stability results of the method for a 7 o half angle blunt cone at Mach 15.99 are compared with ideal gas computations that set their wall temperature and wall blowing from the real gas simulation. Weak planar fast acoustic waves are used to perturb the steady base flow. In the nose region wall normal velocity fluctuations increase three orders of magnitude and then decrease rapidly as the wall mass flux decreases on the cone surface. In the nose region perturbation amplitudes of vibration temperature are two orders of magnitude larger than perturbation ampitudes of translation-rotation temperature. NomenclatureC Mass fraction c v,s Species translation-rotation heat capacity at constant volume J/kgK D Species diffusion coefficient m 2 /s e Specific total energy J/kg e v,s Species specific vibration energy J/kg e v Specific vibration energy J/kg h o Stagnation enthalpy J/kg h o s Species heat of formation J/kg M s Species molecular weight kg/mol m Mass flux per area kg/m 2 · s n Surface normal nms Number of molecular species ns Number of species Q T −V,s Species vibration energy transfer rate J/s R Universal gas constant, 8.3143 J/mol · K r Sphere radius s Surface streamline v w Wall normal velocity m/s Subscripts ∞ Freestream n Normal component s Species t Tangential component w Wall Symbols δ ij Kronecker delta ω sRate of species production kg/m 3 · s ρ Density kg/m 3

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“…9,10 The effects of surface blowing on boundary layer instability have also been studied recently in the context of a flat plate boundary layer. 11,12 This paper is focused on the transition mechanisms due to the effects of out-gassing in the absence of surface roughness. Previous studies related to the effects of blowing on flat plate boundary layers 11,12 are extended first to a slender cone and then to a blunt capsule.…”

Section: Introductionmentioning

confidence: 99%

“…11,12 This paper is focused on the transition mechanisms due to the effects of out-gassing in the absence of surface roughness. Previous studies related to the effects of blowing on flat plate boundary layers 11,12 are extended first to a slender cone and then to a blunt capsule. Results for each of these geometries are presented in Sections III, IV and V below, following a description of the analysis.…”

Section: Introductionmentioning

confidence: 99%

Boundary Layer Transition over Blunt Hypersonic Vehicles Including Effects of Ablation-Induced Out-Gassing

Choudhari

Chang

et al. 2011

6th AIAA Theoretical Fluid Mechanics Conference

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Computations are performed to study the boundary layer instability mechanisms pertaining to hypersonic flow over blunt capsules. For capsules with ablative heat shields, transition may be influenced both by out-gassing associated with surface pyrolysis and the resulting modification of surface geometry including the formation of micro-roughness. To isolate the effects of out-gassing, this paper examines the stability of canonical boundary layer flows over a smooth surface in the presence of gas injection into the boundary layer. For a slender cone, the effects of out-gassing on the predominantly second mode instability are found to be stabilizing. In contrast, for a blunt capsule flow dominated by first mode instability, out-gassing is shown to be destabilizing. Analogous destabilizing effects of outgassing are also noted for both stationary and traveling modes of crossflow instability over a blunt sphere-cone configuration at angle of attack.

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Numerical Simulations of Hypersonic Boundary-Layer Instability with Wall Blowing

Cited by 17 publications

References 8 publications

Effects of injection on the instability of boundary layers over hypersonic configurations

Effects of injection on the instability of boundary layers over hypersonic configurations

High-Order Shock-Fitting Method for Hypersonic Flow with Graphite Ablation and Boundary Layer Stability

Boundary Layer Transition over Blunt Hypersonic Vehicles Including Effects of Ablation-Induced Out-Gassing

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