Reverse Design of Ultrasonic Absorptive Coating for the Stabilization of Mack Modes

Tian, Xudong; Zhao, Rui; Long, Tiehan; Wen, Chih-Yung

doi:10.2514/1.j058105

Cited by 30 publications

(15 citation statements)

References 27 publications

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“…Figure 11 presents snapshots of static pressure perturbations p illustrating the strong growth of waves by many orders of magnitudes over a few tens of centimeters only. Pressure oscillations also appear around the sonic line which is often observed and indicative of secondmode transition 27,46 Finally, Fig. 12 quantifies the growth of wall pressure perturbations and provides a comparison with the previously discussed LST results.…”

Section: Excitation and Stability Analysismentioning

confidence: 70%

“…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%

“…However, the computational cost limited the scale of the simulation over a single second-mode wavelength, focusing on temporal rather than the more relevant spatial instabilities. 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.…”

Section: Introductionmentioning

confidence: 99%

“…Notably, their TDIBC was derived from the scattering operator rather than the impedance operator as was done in previous studies. 23,24,27 The use of the scattering operator was proven by Monteghetti et al 28 to offer better numerical stability than the unbounded impedance operator in grazing flows. The multi-pole approach Sousa et al used allows for a broadband resolution of the UAC spectral response, although no detail on the reflectivity and phase shift resolution was given.…”

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: Excitation and Stability Analysismentioning

confidence: 70%

Section: Introductionmentioning

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

“…More updated progresses could be found in Refs. [25][26][27][28]. Recently, Zhao et al [31] expanded the research subjects by introducing the acoustic metasurface concept.…”

Section: Introductionmentioning

confidence: 99%

Broadband Design of Acoustic Metasurfaces for the Stabilization of a Mach 4 Boundary Layer Flow

Zhao

Xiao

Wen

et al. 2021

Preprint

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A piecewise acoustic metasurface is designed to suppress the first mode while marginally amplifying the Mack second mode in a Mach 4 flat-plate boundary layer (BL) flow. The results of linear stability theory (LST) and the eN method demonstrate the stabilization effect and transition delay performance, respectively. However, the direct numerical simulation (DNS) results indicate that the designed broadband acoustic metasurface actually weakly excites the first mode with a slightly larger fluctuating pressure amplitude at the surface, which is in contrast to the analysis of LST. The discrepancies are found to lie in the ‘roughness’ effect caused by the recirculation zones inside the microslits and the alternating expansion and compression waves induced at the slit edges, which significantly amplifies the first mode. For further clarification of the competitive mechanism between the acoustic stabilization and ‘roughness’ destabilization effects of metasurfaces on the first mode, a carefully designed metasurface is installed at the maximum growth rate region, which excites the first mode on the metasurface but inhibits its development downstream.

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Experiments on the development of natural disturbances in a hypersonic boundary layer on surfaces with microgrooves

2021

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Reverse Design of Ultrasonic Absorptive Coating for the Stabilization of Mack Modes

Cited by 30 publications

References 27 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

Broadband Design of Acoustic Metasurfaces for the Stabilization of a Mach 4 Boundary Layer Flow

Experiments on the development of natural disturbances in a hypersonic boundary layer on surfaces with microgrooves

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