Numerical Investigation of Second-Mode Attenuation over Carbon/Carbon Porous Surfaces

Sousa, Victor C. B.; Patel, Danish; Chapelier, Jean-Baptiste; Wartemann, Viola; Wagner, Alexander; Scalo, Carlo

doi:10.2514/1.a34294

Cited by 37 publications

(24 citation statements)

References 42 publications

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“…18,19 This UAC was successfully used to delay the laminar-to-turbulent transition on a conical surface in an experiment at the High-Enthalpy Goettingen facility mimicking a high altitude Mach 7.4 flight. Specifically, the similarly designed numerical experiment of Sousa et al 26 replicated 28 km-altitude Mach 7.4 flight conditions. The numerical experiment considered herein is designed to match as closely as possible the conditions of these aforementioned studies.…”

Section: Stability Analysis Of a Hypersonic Boundary Layermentioning

confidence: 99%

“…This sensitivity study is motivated by the need to understand how much surface has to be treated to achieve a target reduction of HBL instabilities. Coincidently, new LST calculations are also carried at 260 kHz which use the constant impedance resistivity and reactivity calculated from Sousa et al 26 at this particular frequency. This permits to evaluate the LST ability in locally resolving these complex flows on its own.…”

Section: Effect Of the Uac Positioningmentioning

confidence: 99%

“…Computational studies have also been able to capture the UAC stabilizing effect by either directly resolving the porous coating 21,22 or by modeling its impedance as a boundary condition. [23][24][25][26][27] The direct numerical simulation (DNS) of Brès et al 21 resolved the UAC damping effects using the former method by meshing the pores as uniformly-spaced cavities. This provided important insight on pore-to-pore interactions and revealed the presence of a slip-velocity induced instability in the high-porosity (pores hole to surface ratio) shallow-pores limit.…”

Section: Introductionmentioning

confidence: 99%

“…To circumvent the need to mesh the porosity, time-domain impedance boundary conditions (TDIBC) mimicking the UAC response over a delimited spectral range have been successfully used in linear 23,24,27 and nonlinear solvers alike. 25,26 Of particular interest is the recent work of Sousa et al 25,26 which performed a DNS aimed at capturing the whole transition region with TDIBC calibrated using experimental measurement of UAC impedance. Notably, their TDIBC was derived from the scattering operator rather than the impedance operator as was done in previous studies.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical Study of Hypersonic Boundary-Layer Transition Delay through Second-Mode Absorption

Fiévet¹,

Deniau²,

Brazier³

et al. 2020

AIAA Scitech 2020 Forum

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Numerical time-domain impedance boundary conditions are developed within a highorder spectral difference flow solver. They are designed to accurately replicate the acoustic response of ultrasonically-absorbent coatings over a broad spectral range. The coupling of this class of high-fidelity wall boundary conditions with high-order numerical methods has enabled their use in aero-acoustics applications. This solver is used to perform direct numerical simulations (DNS) of a hypersonic boundary layer and analyze the stabilizing effects of acoustically absorbent materials on the laminar-to-turbulent transition. The damping effectiveness of such complex porous coating on key frequencies of interest is investigated, as well as its effect on the mean flow. It is found that the second-mode instability, which dominates the high-Mach number flow regime, is strongly suppressed at the expense of higher far-field noise radiation. The solutions obtained by means of DNS are also found to compare favorably with linearized stability theory.

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Section: Stability Analysis Of a Hypersonic Boundary Layermentioning

confidence: 99%

Section: Effect Of the Uac Positioningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Study of Hypersonic Boundary-Layer Transition Delay through Second-Mode Absorption

Fiévet¹,

Deniau²,

Brazier³

et al. 2020

AIAA Scitech 2020 Forum

View full text Add to dashboard Cite

show abstract

“…For instance, acoustically-reacting surfaces are used in noise-canceling devices such as acoustic liners [18,19]. Another promising application of such coatings is the canceling of unstable thermo-acoustic modes in combustion chambers [20,21] or boundary layers [22,23,24]. Interestingly, TDIBC can mimick any sort of arbitrarily-complex condition (pure-delay, fully/partially reflecting) provided its analogous impedance be determined and serve a universal purpose.…”

Section: Introductionmentioning

confidence: 99%

Strong compact formalism for characteristic boundary conditions with discontinuous spectral methods

Fiévet

Deniau

Piot

2020

Journal of Computational Physics

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Characteristic boundary conditions for the Navier-Stokes equations (NSCBC) are implemented for the first time with discontinuous spectral methods, namely the spectral difference and flux reconstruction. The implementation makes use of the resolution by these methods of the strong form of the Navier-Stokes equations by applying these conditions through a flux balance regularization which takes the form of a generalized element-compact correction polynomial. It is shown to be at least as effective as similar implementations in finite volume solvers, and sustains arbitrarily-high orders of accuracy on hexahedral-based unstructured meshes. Further, Navier-Stokes time-domain impedance boundary conditions are derived and implemented as a NSCBC sub-class. They account for the diffusive process at the wall and are shown to properly resolve broadband impedance models under normal and grazing flow conditions. The ability of these NSCBC in preventing the appearance of spurious reflections at the boundaries is demonstrated through a varied series of bench-marking simulations. They effectively shield the inner computational domain from any far-field unphysical contamination. Overall, this work enables the use of strong discontinuous spectral methods to study unsteady problems on complex geometries.

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On the inviscid energetics of Mack’s first mode instability

Liang

Kafle

Khan

et al. 2022

Theor. Comput. Fluid Dyn.

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Numerical Investigation of Second-Mode Attenuation over Carbon/Carbon Porous Surfaces

Cited by 37 publications

References 42 publications

Numerical Study of Hypersonic Boundary-Layer Transition Delay through Second-Mode Absorption

Numerical Study of Hypersonic Boundary-Layer Transition Delay through Second-Mode Absorption

Strong compact formalism for characteristic boundary conditions with discontinuous spectral methods

On the inviscid energetics of Mack’s first mode instability

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