Alexander Fedorov | Moscow Institute of Physics and Technology (original) (raw)

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Papers by Alexander Fedorov

Research paper thumbnail of Numerical modelling of supersonic boundary-layer receptivity to solid particulates

Journal of Fluid Mechanics, 2018

Atmospheric particulates may be a major source of boundary-layer instabilities leading to laminar... more Atmospheric particulates may be a major source of boundary-layer instabilities leading to laminar–turbulent transition on aerodynamically smooth bodies flying at supersonic speeds. Particulates penetrating into the boundary-layer flow can excite wavepackets of the first- and/or second-mode instability. The packets grow downstream, reach the threshold amplitude and ultimately break down to turbulent spots. A numerical model is developed to simulate excitation of unstable wavepackets by spherical solid particulates. As an example, computations are carried out for a 14circ14^{\circ }14circ half-angle sharp wedge flying at an altitude of 20 km, Mach number 4 and zero angle of attack. The numerical results agree satisfactorily with the theory developed by Fedorov (J. Fluid Mech., vol. 737, 2013, pp. 105–131). The numerical model opens up an opportunity to investigate receptivity to particulates for practical supersonic and hypersonic configurations such as blunt bodies of revolution.

Research paper thumbnail of Influence of the plate leading-edge shape and thickness on the boundary layer laminar-turbulent transition at Mach number M=5

The results of experimental study of boundary layer laminar-turbulent transition on a blunted pla... more The results of experimental study of boundary layer laminar-turbulent transition on a blunted plate with leading edges of various shapes and thicknesses at free-stream Mach number M=5 and unit Reynolds numbers Re1 from 1.5x107 to 9x107 m-1 are presented. The Reynolds number Reb, calculated by leading edge thickness b, was varied from 0 to 2x106. The following leading edge shapes were studied: cylinder, flat face, ellipse, and \"smoothed cylinder\". They were chosen by the results of numerical study of a non-viscous gas flow around a blunted plate. It was shown that at Reb0.5x105, the shape of the leading edge practically does not affect the transition position. At the same time, the laminar flow segment is monotonously extended as b increases. For large Reb values the variation of leading edge shape significantly changes the transition position. A laminar - turbulent transition reversal was observed for all investigated shapes of leading edge. However, the Reynolds number ...

Research paper thumbnail of Numerical Simulation of Three-Dimensional Wave Packet in Supersonic Flow over a Compression Corner

45th AIAA Fluid Dynamics Conference, 2015

Research paper thumbnail of Theoretical-Numerical Analysis of Boundary-Layer Stability with Combined Injection and Acoustic Absorptive Coating

Research paper thumbnail of Mathematical Fluid Dynamics of Store and Stage Separation, Multi-Body Flows and Flow Control

Research paper thumbnail of Experimental study of the laminar-turbulent transition on a blunt cone

Journal of Applied Mechanics and Technical Physics

ABSTRACT Results of an experimental study of the laminar-turbulent transition in a hypersonic flo... more ABSTRACT Results of an experimental study of the laminar-turbulent transition in a hypersonic flow around cones with different bluntness radii at a zero angle of attack, free-stream Mach number M ∞ = 6, and unit Reynolds number in the interval Re ∞,1 = 5.79 · 106–5.66 · 107 m−1 are presented. Flow regimes in which a reverse of the laminar-turbulent transition (decrease in the length of the laminar segment with increasing bluntness radius) are studied. Heat flux distributions over the model surface are obtained with the use of temperature-sensitive paints. Lines of the beginning of the transition in the boundary layer are analyzed by using heat flux fields. The critical Reynolds number Re ∞,R ≈ 1.3 · 105 beginning from which the laminar-turbulent transition substantially depends on uncontrolled disturbances, such as the model tip roughness, is found. In supercritical regimes, the line of the transition beginning is shifted in most cases toward the model tip (reverse of the transition). The results obtained are compared with available experimental data.

Research paper thumbnail of The extended GrtlerHmmerlin model for linear instability of three-dimensional incompressible swept attachment-line boundary layer flow

Research paper thumbnail of Receptivity of Hypersonic Non-Gradient Boundary Layer to Wall Disturbances

Research paper thumbnail of Laminar Turbulent Transition in a Hypersonic Boundary Layer. Receptivity and Instability Pre-History

Research paper thumbnail of The extended Görtler-Hämmerlin model for linear instability in the three-dimensional incompressible swept attachment line boundary layer

Journal of Fluid Mechanics, 2003

Research paper thumbnail of Receptivity of Hypersonic Boundary Layer to Acoustic Disturbances Scattered by Surface Roughness

Research paper thumbnail of Parametric Studies of Hypersonic Laminar Flow Control Using a Porous Coating of Regular Microstructure

46th AIAA Aerospace Sciences Meeting and Exhibit, 2008

Research paper thumbnail of Modeling of Forebody Nose Vortex Symmetry Breaking Using Conical Navier-Stokes Solutions

44th AIAA Aerospace Sciences Meeting and Exhibit, 2006

Research paper thumbnail of Stability of high-speed boundary layer on a sharp cone with localized wall heating or cooling

Progress in Flight Physics – Volume 7, 2015

Research paper thumbnail of Modeling of Plasma Flow Control Over a High-Speed Delta Wing

47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, 2009

Numerical modeling of vortex flow over a delta wing with sharp leading edges of 60ο sweep angle h... more Numerical modeling of vortex flow over a delta wing with sharp leading edges of 60ο sweep angle has been performed at free-stream Mach number 1.5 and angles of attack from 0ο to 30ο. The flow field contains two strong vortices generated by the rollup of the shear layer ...

Research paper thumbnail of Modeling of Aerodynamic Forcing Induced by Surface Dielectric Barrier Discharge

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

Research paper thumbnail of Instability of Hypersonic Boundary Layer on a Wall with Resonating Micro-Cavities

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

Research paper thumbnail of Susceptibility of a boundary layer to acoustic perturbations

Journal of Applied Mechanics and Technical Physics

A solution is presented to the problem of the excitation of Tollmien-Schlichting waves by externa... more A solution is presented to the problem of the excitation of Tollmien-Schlichting waves by external acoustic waves that are scattered by small local surface irregularities. The amplitudes of the generated instability waves in a boundary layer on a plane plate are calcuated for incoming flow Mach 0.2-0.8. The results are found to be in good agreement with the available experimental data. A comparison is made between the efficiencies of the excitation of Tollmien-Schlichting waves by sound at local irregularities and at distributed flow inhomogeneities due to the nonparallelism of the boundary layer.

Research paper thumbnail of Numerical Simulation of Stability of a Supersonic Near-Wall Flow Past Rounded Compression Corner

International Symposium on Advances in Computational Heat Transfer, 2008

ABSTRACT Two-dimensional direct numerical simulation of stability of a near-wall laminar flow ove... more ABSTRACT Two-dimensional direct numerical simulation of stability of a near-wall laminar flow over a shallow wavy surface is carried out for the freestream Mach = 6. Numerical experiments are conducted for propagation of disturbances generated by a suction-blowing actuator placed on the wall. It is shown that high-frequency forcing excites unstable disturbances in the flat-plate boundary layer relevant to the second mode instability. The amplitude of these disturbances decreases over the wavy wall compared with the flat plate case.

Research paper thumbnail of On Numerical Prediction of the Stability of Hypersonic Boundary-Layer Flow Over a Row of Microcavities

Volume 2: Symposia, Parts A, B, and C, 2003

Page 1. Proceedings of FEDSM'03 2003 ASME JSME Joint Fluids Engineering Conference July 6-10... more Page 1. Proceedings of FEDSM'03 2003 ASME JSME Joint Fluids Engineering Conference July 6-10, 2003, Honolulu, Hawaii USA FEDSM2003-45635 ON NUMERICAL PREDICTION OF THE STABILITY OF HYPERSONIC ...

Research paper thumbnail of Numerical modelling of supersonic boundary-layer receptivity to solid particulates

Journal of Fluid Mechanics, 2018

Atmospheric particulates may be a major source of boundary-layer instabilities leading to laminar... more Atmospheric particulates may be a major source of boundary-layer instabilities leading to laminar–turbulent transition on aerodynamically smooth bodies flying at supersonic speeds. Particulates penetrating into the boundary-layer flow can excite wavepackets of the first- and/or second-mode instability. The packets grow downstream, reach the threshold amplitude and ultimately break down to turbulent spots. A numerical model is developed to simulate excitation of unstable wavepackets by spherical solid particulates. As an example, computations are carried out for a 14circ14^{\circ }14circ half-angle sharp wedge flying at an altitude of 20 km, Mach number 4 and zero angle of attack. The numerical results agree satisfactorily with the theory developed by Fedorov (J. Fluid Mech., vol. 737, 2013, pp. 105–131). The numerical model opens up an opportunity to investigate receptivity to particulates for practical supersonic and hypersonic configurations such as blunt bodies of revolution.

Research paper thumbnail of Influence of the plate leading-edge shape and thickness on the boundary layer laminar-turbulent transition at Mach number M=5

The results of experimental study of boundary layer laminar-turbulent transition on a blunted pla... more The results of experimental study of boundary layer laminar-turbulent transition on a blunted plate with leading edges of various shapes and thicknesses at free-stream Mach number M=5 and unit Reynolds numbers Re1 from 1.5x107 to 9x107 m-1 are presented. The Reynolds number Reb, calculated by leading edge thickness b, was varied from 0 to 2x106. The following leading edge shapes were studied: cylinder, flat face, ellipse, and \"smoothed cylinder\". They were chosen by the results of numerical study of a non-viscous gas flow around a blunted plate. It was shown that at Reb0.5x105, the shape of the leading edge practically does not affect the transition position. At the same time, the laminar flow segment is monotonously extended as b increases. For large Reb values the variation of leading edge shape significantly changes the transition position. A laminar - turbulent transition reversal was observed for all investigated shapes of leading edge. However, the Reynolds number ...

Research paper thumbnail of Numerical Simulation of Three-Dimensional Wave Packet in Supersonic Flow over a Compression Corner

45th AIAA Fluid Dynamics Conference, 2015

Research paper thumbnail of Theoretical-Numerical Analysis of Boundary-Layer Stability with Combined Injection and Acoustic Absorptive Coating

Research paper thumbnail of Mathematical Fluid Dynamics of Store and Stage Separation, Multi-Body Flows and Flow Control

Research paper thumbnail of Experimental study of the laminar-turbulent transition on a blunt cone

Journal of Applied Mechanics and Technical Physics

ABSTRACT Results of an experimental study of the laminar-turbulent transition in a hypersonic flo... more ABSTRACT Results of an experimental study of the laminar-turbulent transition in a hypersonic flow around cones with different bluntness radii at a zero angle of attack, free-stream Mach number M ∞ = 6, and unit Reynolds number in the interval Re ∞,1 = 5.79 · 106–5.66 · 107 m−1 are presented. Flow regimes in which a reverse of the laminar-turbulent transition (decrease in the length of the laminar segment with increasing bluntness radius) are studied. Heat flux distributions over the model surface are obtained with the use of temperature-sensitive paints. Lines of the beginning of the transition in the boundary layer are analyzed by using heat flux fields. The critical Reynolds number Re ∞,R ≈ 1.3 · 105 beginning from which the laminar-turbulent transition substantially depends on uncontrolled disturbances, such as the model tip roughness, is found. In supercritical regimes, the line of the transition beginning is shifted in most cases toward the model tip (reverse of the transition). The results obtained are compared with available experimental data.

Research paper thumbnail of The extended GrtlerHmmerlin model for linear instability of three-dimensional incompressible swept attachment-line boundary layer flow

Research paper thumbnail of Receptivity of Hypersonic Non-Gradient Boundary Layer to Wall Disturbances

Research paper thumbnail of Laminar Turbulent Transition in a Hypersonic Boundary Layer. Receptivity and Instability Pre-History

Research paper thumbnail of The extended Görtler-Hämmerlin model for linear instability in the three-dimensional incompressible swept attachment line boundary layer

Journal of Fluid Mechanics, 2003

Research paper thumbnail of Receptivity of Hypersonic Boundary Layer to Acoustic Disturbances Scattered by Surface Roughness

Research paper thumbnail of Parametric Studies of Hypersonic Laminar Flow Control Using a Porous Coating of Regular Microstructure

46th AIAA Aerospace Sciences Meeting and Exhibit, 2008

Research paper thumbnail of Modeling of Forebody Nose Vortex Symmetry Breaking Using Conical Navier-Stokes Solutions

44th AIAA Aerospace Sciences Meeting and Exhibit, 2006

Research paper thumbnail of Stability of high-speed boundary layer on a sharp cone with localized wall heating or cooling

Progress in Flight Physics – Volume 7, 2015

Research paper thumbnail of Modeling of Plasma Flow Control Over a High-Speed Delta Wing

47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, 2009

Numerical modeling of vortex flow over a delta wing with sharp leading edges of 60ο sweep angle h... more Numerical modeling of vortex flow over a delta wing with sharp leading edges of 60ο sweep angle has been performed at free-stream Mach number 1.5 and angles of attack from 0ο to 30ο. The flow field contains two strong vortices generated by the rollup of the shear layer ...

Research paper thumbnail of Modeling of Aerodynamic Forcing Induced by Surface Dielectric Barrier Discharge

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

Research paper thumbnail of Instability of Hypersonic Boundary Layer on a Wall with Resonating Micro-Cavities

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

Research paper thumbnail of Susceptibility of a boundary layer to acoustic perturbations

Journal of Applied Mechanics and Technical Physics

A solution is presented to the problem of the excitation of Tollmien-Schlichting waves by externa... more A solution is presented to the problem of the excitation of Tollmien-Schlichting waves by external acoustic waves that are scattered by small local surface irregularities. The amplitudes of the generated instability waves in a boundary layer on a plane plate are calcuated for incoming flow Mach 0.2-0.8. The results are found to be in good agreement with the available experimental data. A comparison is made between the efficiencies of the excitation of Tollmien-Schlichting waves by sound at local irregularities and at distributed flow inhomogeneities due to the nonparallelism of the boundary layer.

Research paper thumbnail of Numerical Simulation of Stability of a Supersonic Near-Wall Flow Past Rounded Compression Corner

International Symposium on Advances in Computational Heat Transfer, 2008

ABSTRACT Two-dimensional direct numerical simulation of stability of a near-wall laminar flow ove... more ABSTRACT Two-dimensional direct numerical simulation of stability of a near-wall laminar flow over a shallow wavy surface is carried out for the freestream Mach = 6. Numerical experiments are conducted for propagation of disturbances generated by a suction-blowing actuator placed on the wall. It is shown that high-frequency forcing excites unstable disturbances in the flat-plate boundary layer relevant to the second mode instability. The amplitude of these disturbances decreases over the wavy wall compared with the flat plate case.

Research paper thumbnail of On Numerical Prediction of the Stability of Hypersonic Boundary-Layer Flow Over a Row of Microcavities

Volume 2: Symposia, Parts A, B, and C, 2003

Page 1. Proceedings of FEDSM'03 2003 ASME JSME Joint Fluids Engineering Conference July 6-10... more Page 1. Proceedings of FEDSM'03 2003 ASME JSME Joint Fluids Engineering Conference July 6-10, 2003, Honolulu, Hawaii USA FEDSM2003-45635 ON NUMERICAL PREDICTION OF THE STABILITY OF HYPERSONIC ...