Stabilization of Hypersonic Boundary Layers by Porous Coatings

Федоров, А. В.; Malmuth, N.; Rasheed, Adam; Hornung, H. G.

doi:10.2514/2.1382

Cited by 215 publications

(58 citation statements)

References 20 publications

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“…Previous numerical simulations [3] have suggested that UAC performance increases with porosity, and our parametric study tends to confirm this result. Overall, the amplitude of the reflection coefficient decreases with higher porosity, as the scattering and absorption of acoustic waves by the UAC is enhanced.…”

Section: E Guidelines For Uac Designsupporting

confidence: 74%

“…The width 0:1 was found to be adequate to accurately resolve frequencies up to f f H=a 0 2. For typical UAC parameters, this range of frequencies corresponds to the ultrasonicfrequency band and is sufficient to capture the frequency of the most amplified second-mode instability waves observed in experiments [4,13] and numerical simulations [3,14,15].…”

Section: B Computational Setupmentioning

confidence: 99%

“…Wind-tunnel experiments and theoretical studies [3][4][5][6][7][8] have already demonstrated that an ultrasonically absorptive coating (UAC), which consists of a thin microporous layer, can suppress the second-mode instability and thereby delay transition of the predominately-two-dimensional boundary layer. Integration of this passive UAC device to thermal protection systems requires multidisciplinary efforts, including flow modeling, testing of materials and fabrication of prototypes.…”

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confidence: 99%

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Acoustic Properties of Porous Coatings for Hypersonic Boundary-Layer Control

2010

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Numerical simulations are performed to investigate the interaction of acoustic waves with an array of equally spaced two-dimensional microcavities on an otherwise flat plate without external boundary-layer flow. This acoustic scattering problem is important in the design of ultrasonic absorptive coatings for hypersonic laminar flow control. The reflection coefficient, characterizing the ratio of the reflected wave amplitude to the incident wave amplitude, is computed as a function of the acoustic wave frequency and angle of incidence, for coatings of different porosities, at various acoustic Reynolds numbers relevant to hypersonic flight. Overall, the numerical results validate predictions from existing theoretical modeling. In general, the amplitude of the reflection coefficient has local minima at some specific frequencies. A simple model to predict these frequencies is presented. The simulations also highlight the presence of resonant acoustic modes caused by coupling of small-scale scattered waves near the coating surface. Finally, the cavity depth and the porosity are identified as the most important parameters for coating design. Guidelines for the choice of these parameters are suggested.

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Section: E Guidelines For Uac Designsupporting

confidence: 74%

Section: B Computational Setupmentioning

confidence: 99%

mentioning

confidence: 99%

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Acoustic Properties of Porous Coatings for Hypersonic Boundary-Layer Control

2010

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“…In previous experiments and numerical simulations, papers [1,3,4,5] demonstrated that porous materials on the flat plate and cone surface in a hypersonic flow suppress disturbances arising in the boundary layer, extend the laminar flow regime, and reduce the friction drag. These phenomena are based on dissipation of the energy of acoustic disturbances, which are a dominating mode of instability of a hypersonic boundary layer, owing to friction in pores of the coating.…”

Section: Figure 1 Permeable Highly Porous Cellular Materials (Hpcm): mentioning

confidence: 99%

Numerical simulation of highly porous materials in application to supersonic aerodynamics

Poplavskaya

Kirilovskiy

Mironov

et al. 2017

AIP Conference Proceedings

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Abstract. Within the framework of the skeleton model of a porous medium, numerical simulation of two tasks was performed: task of the absorption of acoustic disturbances at hypersonic flow past a plate with a porous insert taking into account the real properties of the gas and task of a supersonic flow around a streamwise aligned cylinder with a frontal insert from cellular porous nickel. It is shown that high porous cellular materials can effectively be used in supersonic aerodynamics.

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“…The cause of the transition in hypersonic gradientless boundary layers is high frequencies unstable disturbances so called second mode disturbances [1]. On the passive porous coating with microstructure second mode disturbances grows slower than on the smooth surface [2]. The ability to delay transition by passive porous coatings are shown in several works [2 -4].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the influence of the passive porous coating on laminar-turbulent transition of the hypersonic boundary layer of the sharp cone at angles of attack

2017

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Abstract. The problem of the delaying laminar to turbulent transition by the passive porous coating on the sharp cone at the angle of attack has been studied for the first time. Experiments are conducted in a Transit-M hypersonic short-duration wind tunnel at the Mach number 5.9. The boundary layer laminar-turbulent transition is determined by heat flux distribution on the surface of the cone. It is found that the transition on the porous surface in compare to smooth surface has been delaying on the windward side at the 0.5°, 1° and on leeward side at the 0.5°. There is no effect of the porous coating on the location of the laminar to turbulent transition at angle of attack 1°.

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Stabilization of Hypersonic Boundary Layers by Porous Coatings

Cited by 215 publications

References 20 publications

Acoustic Properties of Porous Coatings for Hypersonic Boundary-Layer Control

Acoustic Properties of Porous Coatings for Hypersonic Boundary-Layer Control

Numerical simulation of highly porous materials in application to supersonic aerodynamics

Experimental investigation of the influence of the passive porous coating on laminar-turbulent transition of the hypersonic boundary layer of the sharp cone at angles of attack

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