Statistical Analysis of Nonlinear Processes on a Porous Surface in a Hypersonic Boundary Layer

2009 ◽  
Vol 4 (3) ◽  
pp. 43-49
Author(s):  
Dmitriy Buntin ◽  
Anatoliy Maslov ◽  
Timur Chimytov ◽  
Aleksandr Shiplyuk
Keyword(s):  
Boundary Layer ◽  
Statistical Analysis ◽  
Porous Surface ◽  
Transition To Turbulence ◽  
Hypersonic Boundary Layer ◽  
Hot Wire ◽  
Turbulent Transition ◽  
Hypersonic Wind Tunnel ◽  
Sharp Cone ◽  
Skewness And Kurtosis

Experimental investigation of nonlinear stage of the transition to turbulence in a hypersonic boundary layer is presented. The experiments were carried out in a hypersonic wind tunnel T-326 at the Institute of theoretical and applied mechanics SB RAS. The model was a sharp cone with porous surface. Using the statistical analysis of the signals obtained by means of hot-wire it was shown that skewness and kurtosis distribution in a boundary layer on both solid and porous surface are in a qualitative agreement. At the same time the growing of skewness and kurtosis on a porous surface was shown. Analysis of mean voltage and rms voltage pulsation profiles of the hot-wire sensors showed that there is a delay of the laminar-turbulent transition on a porous surface.

scholarly journals Shock-induced heating and transition to turbulence in a hypersonic boundary layer

2020 ◽  
Vol 909 ◽  
Author(s):  
Lin Fu ◽  
Michael Karp ◽  
Sanjeeb T. Bose ◽  
Parviz Moin ◽  
Javier Urzay
Keyword(s):  
Boundary Layer ◽  
Transition To Turbulence ◽  
Hypersonic Boundary Layer

Abstract

An experiment on the stability of hypersonic laminar boundary layers

1960 ◽  
Vol 7 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Anthony Demetriades
Keyword(s):  
Boundary Layer ◽  
Flat Surface ◽  
Hypersonic Boundary Layer ◽  
Natural Disturbances ◽  
Hot Wire ◽  
Amplitude Variation ◽  
Laminar Boundary Layers ◽  
Boundary Layer Instability ◽  
The Stability ◽  
Maximum Amplification

An experimental investigation of the hydrodynamic stability of the laminar hypersonic boundary layer was carried out with the aid of a hot-wire anemometer. The case investigated was that of a flat surface at zero angle of attack and no heat transfer.The streamwise amplitude variation of both natural disturbances and of disturbances artifically excited with a siren mechanism was studied. In both cases it was found that such small fluctuations amplify for certain ranges of frequency and Reynolds number Rθ, and damp for others. The demarcation boundaries for the amplification (instability) zone were found to resemble the corresponding limits of boundary-layer instability at lower speeds. A ‘line of maximum amplification’ of disturbances was also found. The amplification rates and hence the degree of selectivity of the hypersonic layer were found, however, to be considerably lower than those at the lower speeds. The disturbances selected by the layer for maximum amplifications have a wavelength which was estimated to be about twenty times the boundary-layer thickness δ.

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.

Investigation of the Effect of Inlet Turbulence on Transitional Wall-Bounded Flows

2017 ◽  
Author(s):  
Burak Ahmet Tuna ◽  
Xianguo Li ◽  
Serhiy Yarusevych
Keyword(s):  
Boundary Layer ◽  
Turbulence Intensity ◽  
Initial Conditions ◽  
Hydraulic Diameter ◽  
Transition To Turbulence ◽  
Duct Flow ◽  
Entrance Length ◽  
Hot Wire ◽  
Boundary Layer Development ◽  
Layer Development

The present work investigates experimentally the effects of grid-generated turbulence on the transition and the hydrodynamic entrance length in a developing duct flow. Particle Image Velocimetry (PIV) and hot-wire anemometry are used to characterize the flow in a rectangular duct with a length of 1m (∼40Dh) and an aspect ratio of 2 (20mm × 40mm). The inlet turbulence intensity is controlled using different grids, and experiments are performed for a Reynolds number based on hydraulic diameter ReDh = 17,750. Hot-wire and PIV results show that the inlet turbulence intensity has a substantial effect on the flow evolution in the duct, as it substantially changes the boundary layer characteristics in the hydrodynamic entrance region. Analysis shows that, as expected, transition to turbulence advances upstream as the inlet turbulence intensity increases, leading to the decrease in the entrance length. The primary effect is confined to boundary layer development, as the turbulence intensity decays rapidly in the core flow, becoming independent of the initial conditions after about 10 hydraulic diameter (Dh) downstream from the grid. Thus, the analysis is focused on characterizing the boundary layer development and quantifying the associated changes in the flow development along the duct.

Quantitative Hot-Wire Measurements in Supersonic Boundary Layers

2003 ◽  
Author(s):  
Eric H. Matlis ◽  
Thomas C. Corke
Keyword(s):  
Boundary Layer ◽  
Supersonic Boundary Layer ◽  
Experimental Measurements ◽  
Hot Wire ◽  
Suction System ◽  
Time Resolved ◽  
Wave Numbers ◽  
The Mean ◽  
Sharp Cone ◽  
Langley Research Center

Mean and time-resolved measurements in a supersonic boundary layer were performed in the Mach 3.5 quiet tunnel facility at the NASA Langley Research Center. This facility uses an annular bleed suction system to remove the turbulent boundary layer, thus reducing the disturbance intensities in the measurement region. A frequency-compensatedconstant current hot-wire anemometer was used to obtain fluctuation data in the boundary layer of a sharp cone at zero angle of attack. The hotwire was calibrated against the mean mass-flux profiles provided by solutions of the similarity profiles for compressible Blasius flow. A stability analysis code provided by Langley was used to solve parabolized stability equations to provide predictions of the most amplified wave-numbers, frequencies, and N-factors for the Tollmien-Schlicting instability. The results from these computations are compared to the experimental measurements performed with the anemometer. In addition, these measurements are compared to spectra obtained in high-disturbance conditions with the bleed system turned off.

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