Effect of sound-absorbing materials on intensity of disturbances in the shock layer on a flat plate aligned at an angle of attack

Маслов, А. А.; Mironov, S. G.; Poplavskaya, T. V.; Tsyryulnikov, I. S.; Kirilovskiy, S. V.

doi:10.1134/s0021894412020034

Cited by 15 publications

(6 citation statements)

References 12 publications

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“…Table 1 shows the parameters of the freestream flow, at which the evolution of perturbations in a viscous shock layer on a plate in the hightemperature hypersonic flow of mixtures of CO 2 Sound-absorbing coating of HPCM under conditions of high flow modeled by direct assignment porous material geometry. The sound-absorbing insert 20 mm in depth was located from x = 90mm to x = 170mm and had the appearance of a regular cellular structure consisting of square-shaped elements arranged in staggered order, similar to [3]. The distance between the skeleton elements in the axial and radial direction was equal to the pore diameter.…”

Section: Methods Of Sound-absorbing Coatings In Vibrationally Excited mentioning

confidence: 99%

“…Plates with inserts of metal felt were successfully used to absorb the acoustic mode of perturbations in the hypersonic (M = 6) boundary layer on the cone in experiments [1], mesh materials -in experiments [2]. It was possible to suppress acoustic disturbances in the shock layer on a plate flowing through a nitrogen stream at M = 21 with the help of inserts from HPCM in experiments [3].…”

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

confidence: 99%

“…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%

“…Figure 3b presents the results of experimental and numerical simulation of the effect of an acoustic-absorbing coating on the surface of a plate in the flow of CO 2 mixtures with air in the form of a ratio of root-mean-square pulsation amplitudes p 3 on the plate surface behind a porous insert (x = 180 mm) to pressure pulsations p 2 in the same place on a solid plate for different disturbance frequencies. The ratio of the pulsation amplitudes of the pressure p 3 …”

Section: Figurementioning

confidence: 99%

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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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Section: Methods Of Sound-absorbing Coatings In Vibrationally Excited mentioning

confidence: 99%

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

confidence: 99%

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

confidence: 99%

Section: Figurementioning

confidence: 99%

See 2 more Smart Citations

Numerical simulation of highly porous materials in application to supersonic aerodynamics

Poplavskaya

Kirilovskiy

Mironov

et al. 2017

AIP Conference Proceedings

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“…One of the known methods for controlling the laminar-turbulent transition in moderately hypersonic flows is the method of applying a sound-absorbing coating onto the surface [5]. The method of sound-absorbing coatings has proved its effectiveness for low-temperature flows at М=21 [6]. It is shown [7] that the method of sound-absorbing coatings is also effective in hypersonic flows of vibrationally excited carbon dioxide.…”

mentioning

confidence: 99%

Effect of sound-absorbing coatings on the disturbance evolution in a flow of a mixture of vibrationally excited gases

Reshetova

Poplavskaya

Kirilovskiy

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. The flow around a solid plate and a plate with a sound-absorbing coating at a nonzero angle of attack in a hypersonic flow (М=8.44) of a mixture of vibrationally excited carbon dioxide and nitrogen is considered. Numerical simulations are performed by solving twodimensional unsteady Navier-Stokes equations with a two-temperature model of relaxing flows. The vibrational energy as a function of time is defined by the Landau−Teller equation. A skeleton model, which is a set of square elements arranged in a staggered order, is used for simulating the porous coating made of foamed nickel with a porosity coefficient of 95%. The distance between the elements is equal to the pore diameter of the real sound-absorbing material. Data on the evolution of disturbances on the solid plate and on the plate with the soundabsorbing coating are presented for various angles of attack and CO2 concentrations in the mixture. The experimental and calculated data on pressure fluctuations on the plate surfaces are found to be in good agreement. The effects of various parameters of the sound-absorbing coating (depth, length, and location at the flat plate) are considered. It is shown that the soundabsorbing coating significantly reduces the intensity of pressure fluctuations on the plate surface as compared to the solid surface (up to 50% depending on the length and location of the sound-absorbing coating). IntroductionThe possibility of controlling the intensity of disturbances in boundary layers and the transition to turbulence is one of the important aspects of the development of perspective hypersonic aircraft. Real gas effects associated with excitation of vibrational degrees of freedom of molecules and flow nonequilibrium are manifested under real flight conditions, where high speeds and temperatures are observed. Real gas properties can significantly affect the generation and evolution of disturbances in the boundary layer and, as a consequence, the transition to turbulence. Nowadays large scientific experience has been accumulated in studying the effect of physical and chemical processes in gases on the mean flow around bodies at hypersonic velocities [1]. However, there are only a few papers on stability of such flows (e.g., [2][3][4]).Disturbances formed in the shock layer are carried downstream and affect the evolution of disturbances and the laminar-turbulent transition in the hypersonic boundary layer on a model. One of the known methods for controlling the laminar-turbulent transition in moderately hypersonic flows is the method of applying a sound-absorbing coating onto the surface [5]. The method of sound-absorbing coatings has proved its effectiveness for low-temperature flows at М=21 [6]. It is shown [7] that the method of sound-absorbing coatings is also effective in hypersonic flows of vibrationally excited carbon dioxide. However, the intensity of relaxation processes and their influence on the evolution of disturbances in a mixture with other gases can differ from the processes in pure CO2.The present res...

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Supersonic flow around a cylinder with a permeable high-porosity insert: experiment and numerical simulation

et al. 2019

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Results of experimental and numerical investigations of a supersonic flow around a cylinder with a frontal gas-permeable insert made of a high-porosity cellular material are presented. The measurements are performed in a T-327 supersonic blowdown wind tunnel at the free-stream Mach numbers $M_{\infty }=4.85$, 7 and 21 in the range of the unit Reynolds numbers $Re_{1\infty }=(0.6{-}13.5)\times 10^{6}~\text{m}^{-1}$. The drag coefficients for a cylinder with an aerospike and a cylinder with a frontal gas-permeable porous insert are obtained. For the cylinder with the frontal gas-permeable porous insert, variations of the insert length, cylinder diameter and pore size are considered, and the mechanism of drag reduction is found, which includes two supplementary processes: attenuation of the bow shock wave in a system of weaker shock waves, and formation of an effective pointed body. The experiments are accompanied by numerical simulations of the flow around the cylinder with the frontal high-porosity insert: the fields of parameters of the external flow and the flow inside the porous insert are obtained, the drag coefficients are calculated, and the shape of the effective body for the examined model is found. The structure of the high-porosity material is modelled by a system of staggered rings of different diameters aligned in the radial and longitudinal directions (skeleton model of a porous medium). Numerical simulations of the problem are performed by means of solving two-dimensional Reynolds-averaged Navier–Stokes equations written in an axisymmetric form. The experimental and numerical data reveal significant drag reduction in a wide range of supersonic flow conditions. The results obtained on the drag coefficient for the cylinder are generalized with the use of a parameter which includes the ratio of the cylinder diameter to the pore diameter in the insert and the Mach number. This parameter is proposed as a similarity criterion for the problem of a supersonic flow around a cylinder with a frontal high-porosity insert.

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Effect of sound-absorbing materials on intensity of disturbances in the shock layer on a flat plate aligned at an angle of attack

Cited by 15 publications

References 12 publications

Numerical simulation of highly porous materials in application to supersonic aerodynamics

Numerical simulation of highly porous materials in application to supersonic aerodynamics

Effect of sound-absorbing coatings on the disturbance evolution in a flow of a mixture of vibrationally excited gases

Supersonic flow around a cylinder with a permeable high-porosity insert: experiment and numerical simulation

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