scholarly journals Stability of Supersonic Boundary Layer on the Sublimation Surface

2020 ◽  
Vol 15 (1) ◽  
pp. 42-61
Author(s):  
Vladimir I. Lysenko ◽  
Sergey A. Gaponov ◽  
Boris V. Smorodsky ◽  
Alexander D. Kosinov ◽  
Mikhail I. Yaroslavtsev
Keyword(s):  
Boundary Layer ◽  
Surface Coating ◽  
Plate Boundary ◽  
Supersonic Boundary Layer ◽  
Linear Stability Theory ◽  
Stagnation Temperature ◽  
Local Growth ◽  
Increasing Temperature ◽  
Effect Of Surface ◽  
Triple Point Temperature

Theoretical investigation of the supersonic flat-plate boundary-layer properties under conditions of the surface material sublimation has been performed for Mach number M = 2. Naphthalene (C10H8) was chosen as the substance for the sublimation coating. Performed computations show that with increasing surface temperature due to stagnation temperature increase, the mass flow rate of naphthalene evaporation increases. Calculations performed on the basis of linear stability theory show that such an increase of evaporation leads to a noticeable decrease of the local growth rates of unstable perturbations in the boundary layer. It is found that stabilization of the boundary layer by the surface coating sublimation occurs with increasing temperature of the sublimation coating, reaching a maximum near the triple point temperature of the sublimation material. The carried out experiments confirmed the stabilizing effect of surface sublimation.

On The Influence Of Porous Coating Thickness On Supersonic Boundary Layer Stability

2015 ◽  
Vol 10 (3) ◽  
pp. 41-47
Author(s):  
Vladimir Lysenko ◽  
Sergey Gaponov ◽  
Boris Smorodsky ◽  
Yuri Yermolaev ◽  
Aleksandr Kosinov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Coating Thickness ◽  
Free Stream ◽  
Plate Boundary ◽  
Quantitative Agreement ◽  
Supersonic Boundary Layer ◽  
Linear Stability Theory ◽  
Porous Coating ◽  
Free Stream Mach Number ◽  
The Stability

Theoretical and experimental investigation of the influence of porous-coating thickness on the stability of the supersonic flat-plate boundary layer at free-stream Mach number M = 2 have been performed. Good quantitative agreement of experimental data obtained with artificially generated disturbances performed on models with various porous inserts and calculations based on the linear stability theory has been achieved. It is shown that the increase of the porous-coating thickness leads to the boundary layer destabilization.

Combined influence of coating permeability and roughness on supersonic boundary layer stability and transition

2016 ◽  
Vol 798 ◽  
pp. 751-773 ◽  
Author(s):  
V. I. Lysenko ◽  
S. A. Gaponov ◽  
B. V. Smorodsky ◽  
Yu. G. Yermolaev ◽  
A. D. Kosinov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Plate Boundary ◽  
Leading Edge ◽  
Quantitative Agreement ◽  
Supersonic Boundary Layer ◽  
Linear Stability Theory ◽  
Porous Coating ◽  
Boundary Layer Stability ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

A joint theoretical and experimental investigation of the influence of the surface permeability and roughness on the stability and laminar–turbulent transition of a supersonic flat-plate boundary layer at a free-stream Mach number of $M_{\infty }=2$ has been performed. Good quantitative agreement of the experimental data obtained with artificially generated disturbances performed on models with various porous inserts and calculations based on linear stability theory has been achieved. An increase of the pore size and porous-coating thickness leads to a boundary layer destabilization that accelerates the laminar–turbulent transition. It is shown that as a certain (critical) roughness value is reached, with an increase in the thickness of the rough and porous coating, the boundary layer stability diminishes and the laminar–turbulent transition is displaced towards the leading edge of the model.

scholarly journals Experiments on Supersonic Boundary Layer Laminarization by Means of Foreign-Gas Injection

2019 ◽  
Vol 14 (3) ◽  
pp. 26-38
Author(s):  
V. I. Lysenko ◽  
B. V. Smorodsky ◽  
Yu. G. Yermolaev ◽  
A. A. Yatskih ◽  
A. D. Kosinov
Keyword(s):  
Boundary Layer ◽  
Sulfur Hexafluoride ◽  
Free Stream ◽  
Plate Boundary ◽  
Quantitative Agreement ◽  
Supersonic Boundary Layer ◽  
Linear Stability Theory ◽  
Free Stream Mach Number ◽  
Heavy Gas ◽  
First Time

Experimental investigation of the influence of the distributed heavy gas (sulfur hexafluoride, SF6) injection into the near-wall sub-layer of a boundary layer) on the hydrodynamic stability in relation to controlled disturbances of the supersonic flat-plate boundary-layer at free-stream Mach number M = 2 have been performed. It was for the first time in controlled experiments obtained that injection of this foreign gas leads to the boundary-layer stabilization that is manifested in reduction of disturbance amplification rates. Good quantitative agreement of collected experimental data with computations based on the linear stability theory is obtained.

Numerical investigation of the nonlinear transition regime in a Mach 2 boundary layer

2010 ◽  
Vol 668 ◽  
pp. 113-149 ◽  
Author(s):  
CHRISTIAN S. J. MAYER ◽  
STEFAN WERNZ ◽  
HERMANN F. FASEL
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Plate Boundary ◽  
Transition Process ◽  
Supersonic Boundary Layer ◽  
Subharmonic Resonance ◽  
Linear Stability Theory ◽  
Experimental Investigations ◽  
Weakly Nonlinear ◽  
Breakdown Mechanism

The transition process in a supersonic flat-plate boundary layer at Mach 2 is investigated numerically using linear stability theory (LST) and direct numerical simulations (DNS). The experimental investigations by Kosinov and his co-workers serve as a reference and provide the physical conditions for the numerical set-up. In these experiments, the weakly nonlinear regime of transition was studied. This led to the discovery of asymmetric subharmonic resonance triads, which appear to be relevant for transition in a Mach 2 boundary layer. These triads were composed of one primary oblique wave of frequency 20kHz and two oblique subharmonic waves of frequency 10kHz. While the experimentalists have focused on this new breakdown mechanism, we have found that the experimental data also indicate the presence of another mechanism related to oblique breakdown. This might be the first experimental evidence of the oblique breakdown mechanism in a supersonic boundary layer. With the simulations presented here, the possible presence of oblique breakdown mechanisms in the experiments is explored by deliberately suppressing subharmonic resonances in the DNS and by comparing the numerical results with the experimental data. The DNS results show excellent agreement with the experimental measurements for both linear and nonlinear transition stages. Most importantly, the results clearly show the characteristic features of oblique breakdown. In addition, we also investigated the subharmonic transition route using LST and DNS. When forcing both the subharmonic and the fundamental frequencies in the DNS, a subharmonic resonance mechanism similar to that in the experiments can be observed.

scholarly journals The influence of moderate angle-of-attack variation on disturbances evolution and transition to turbulence in supersonic boundary layer on swept wing

2019 ◽  
Vol 234 (1) ◽  
pp. 96-101
Author(s):  
Alexander Kosinov ◽  
Nikolai Semionov ◽  
Yury Yermolaev ◽  
Boris Smorodsky ◽  
Gleb Kolosov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Theoretical Study ◽  
Angle Of Attack ◽  
Reynolds Numbers ◽  
Supersonic Boundary Layer ◽  
Linear Stability Theory ◽  
Transition To Turbulence ◽  
Computational Results ◽  
Swept Wing ◽  
Turbulent Transition

The paper is devoted to an experimental and theoretical study of effect of moderate angle-of-attack variation on disturbances evolution and laminar-turbulent transition in a supersonic boundary layer on swept wing at Mach 2. Monotonous growth of the transition Reynolds numbers with angle of attack increasing from −2° to 2.7° is confirmed. For the same conditions, calculations based on linear stability theory are performed. The experimental and computational results show a favourable comparison.

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

2021 ◽  
Author(s):  
Rui Zhao ◽  
Xiao Liu ◽  
Chih-Yung Wen ◽  
Xiaoyong Wang
Keyword(s):  
Boundary Layer ◽  
Plate Boundary ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Linear Stability Theory ◽  
Pressure Amplitude ◽  
Delay Performance ◽  
Compression Waves ◽  
Layer Flow ◽  
Transition Delay

Abstract 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.

Receptivity of a supersonic boundary layer to solid particulates

2013 ◽  
Vol 737 ◽  
pp. 105-131 ◽  
Author(s):  
Alexander V. Fedorov
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Threshold Value ◽  
Supersonic Boundary Layer ◽  
Solid Particles ◽  
Linear Stability Theory ◽  
Spherical Particles ◽  
Standard Atmosphere ◽  
Tollmien Schlichting ◽  
Layer Flow

AbstractLaminar–turbulent transition in the boundary layer at supersonic speeds can be initiated by small solid particles present in the free stream. Particulates interacting with the boundary-layer flow generate unstable wavepackets related to Tollmien–Schlichting (TS) waves. The latter grow downstream and ultimately break down to turbulent spots. This scenario of TS-dominated transition is modelled using the Mack amplitude method. A theoretical model describing the receptivity mechanism is developed to predict the initial spectrum of TS waves. With these initial conditions the downstream growth of TS instability is calculated using the linear stability theory. The transition onset is associated with the point where the disturbance amplitude reaches a threshold value. As an example, calculations are carried out for a 14° half-angle sharp wedge flying in the standard atmosphere at altitude 20 km, Mach number 4 and zero angle of attack. It is shown that spherical particles of radius from $10$ to $20~\unicode[.5,0][STIXGeneral,Times]{x03BC} \mathrm{m} $ and density ${\geqslant }1~\mathrm{g} ~{\mathrm{cm} }^{- 3} $ can cause transition onset corresponding to the amplification factor $N= 9{\unicode{x2013}} 10$, which is in the empirical range of flight data. This indicates that atmospheric particulates may be a major source of TS-dominated transition on aerodynamically smooth surfaces at supersonic speeds. The receptivity model provides a foundation for further treatments of different cases associated with transition in dusty environments. It can also be used for predictions of particle-induced transition at subsonic and hypersonic speeds.

Joint Influence Of Surface Roughness And Permeability On Stability And Transition Of Mach = 2 Boundary Layer

2016 ◽  
Vol 11 (2) ◽  
pp. 37-45
Author(s):  
Vladimir Lysenko ◽  
Boris Smorodsky ◽  
Yuri Yermolaev ◽  
Aleksandr Kosinov ◽  
Nikolay Semionov
Keyword(s):  
Boundary Layer ◽  
Plate Boundary ◽  
Leading Edge ◽  
Quantitative Agreement ◽  
Linear Stability Theory ◽  
Porous Coating ◽  
Boundary Layer Stability ◽  
Turbulent Transition ◽  
Surface Permeability ◽  
Laminar Turbulent Transition

Joint theoretical and experimental investigation of the influence of surface permeability and roughness on stability and laminar-turbulent transition of the supersonic flat-plate boundary layer at free-stream Mach number M = 2 have been performed. Good quantitative agreement of experimental data obtained with artificially generated disturbances performed on models with various porous inserts and calculations based on the linear stability theory has been achieved. At research of the joint effect of the model surface permeability and roughness on the boundary layer stability and transition, it is shown that, as a certain (critical) roughness value is reached, with the rough and porous coating thickness increase, the boundary layer stability diminishes and the laminar-turbulent transition is displaced toward the model leading edge.

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