The stability of the subsonic boundary layer during heating of the surface of a flat plate near the leading edge

Theoretical and an experimental research results of the disturbances development in a swept wing boundary layer are presented at Mach number М = 2. In experiments development of natural and small amplitude controllable disturbances downstream was studied. Experiments were carried out on a swept wing model with a lenticular profile at a zero attack angle. The swept angle of a leading edge was 40°. Wave parameters of moving disturbances were determined. In frames of the linear theory and an approach of the local self-similar mean flow the stability of a compressible three-dimensional boundary layer is studied. Good agreement of the theory with experimental results for transversal scales of unstable vertices of the secondary flow was obtained. However the calculated amplification rates differ from measured values considerably. This disagreement is explained by the nonlinear processes observed in experiment

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ON THE NATURE OF THE BOUNDARY LAYER NEAR THE LEADING EDGE OF A FLAT PLATE

Selected Papers of C C Lin with Commentary ◽

10.1142/9789814415651_0018 ◽

1987 ◽

pp. 283-288

Author(s):

G. F. CARRIER ◽

C. C. LIN

Keyword(s):

Boundary Layer ◽

Flat Plate ◽

Leading Edge

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Experimental study of weak shock waves influence on the supersonic boundary layer of the flat plate model

EPJ Web of Conferences ◽

10.1051/epjconf/201919600018 ◽

2019 ◽

Vol 196 ◽

pp. 00018 ◽

Cited By ~ 2

Author(s):

Vasiliy Kocharin ◽

Aleksandr Kosinov ◽

Yuriy Yermolayev ◽

Nikolay Semionov

Keyword(s):

Boundary Layer ◽

Experimental Study ◽

Shock Waves ◽

Flat Plate ◽

Leading Edge ◽

Weak Shock ◽

Supersonic Boundary Layer ◽

Complex Flow ◽

Complex Flow Structure ◽

Constant Temperature Anemometer

The experimental study of the effect of weak shock waves on the supersonic boundary layer of the flat plate with a blunt leading edge (the radius of bluntness was r = 2.5 mm) with Mach number M = 2.5 and zero angle of attack was carried out. The measurements were carried out using the constant temperature anemometer. The paper presents a complex flow structure on the surface of the model. High-intensity peaks were found in the regions of the disturbed flow. Also the spectral analysis of perturbations was performed. It is found that the supersonic boundary layer on a flat plate is very sensitive to the effect of weak shock waves.

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The Evolution of Streamwise Counter-Rotating Vortices in Flat Plate Boundary Layer With Leading Edge Pattern

Volume 7A: Fluids Engineering Systems and Technologies ◽

10.1115/imece2015-52897 ◽

2015 ◽

Author(s):

Seyed Mohammad Hasheminejad ◽

Hatsari Mitsudharmadi ◽

S. H. Winoto ◽

Kim Boon Lua ◽

Hong Tong Low

Keyword(s):

Boundary Layer ◽

Flat Plate ◽

Plate Boundary ◽

Leading Edge ◽

Streamwise Vortex ◽

Streamwise Velocity ◽

Stream Velocity ◽

Hot Wire ◽

Layer Flow ◽

Different Characteristics

The evolution of streamwise counter-rotating vortices induced by different leading edge patterns is investigated quantitatively using hot-wire anemometer. A notched and triangular leading edge with the same wavelength and amplitude were designed to induce streamwise vortices over a flat plate at Reynolds number (based on the wavelength of the leading edge patterns) of 3080 corresponding to free-stream velocity of 3 m/s. The streamwise velocity at different streamwise locations collected and analyzed using a single wire probe hot-wire anemometer showed reveal different characteristics of boundary layer flow due to the presence of these two leading edge patterns. The major difference is the appearance of an additional streamwise vortex between the troughs of the notched pattern. Such vortices increase the mixing effect in the boundary layer as well as the velocity profile.

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Some Experiments on the Reattachment of a Laminar Boundary Layer Separating From a Rearward Facing Step on a Flat Plate Aerofoil

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100073648 ◽

1960 ◽

Vol 64 (599) ◽

pp. 668-672 ◽

Cited By ~ 13

Author(s):

T. W. F. Moore

Keyword(s):

Boundary Layer ◽

Liquid Film ◽

Flat Plate ◽

Laminar Boundary Layer ◽

Reverse Flow ◽

Leading Edge ◽

Reynolds Numbers ◽

Pressure Measurements ◽

Flow Vortex

Summary:The results of experiments on the reattachment of a laminar boundary layer, separating from a rearward facing step in a flat plate aerofoil, are correlated with the properties of the short leading edge bubble which forms on thin aerofoils near the stall.The experiments, comprising pressure measurements, Pitot explorations, liquid film and smoke studies, indicate that for all Reynolds numbers above the value given by the Owen-KIanfer criterion the reattachment is turbulent behind a stationary air reverse flow vortex bubble. It is also found that the reattachment is laminar for Reynolds numbers below the critical, which further supports Crabtree's interpretation of the Owen-KIanfer criterion in terms of the condition for the growth of turbulent bursts.

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Compressible laminar boundary-layer flows of a dusty gas over a semi-infinite flat plate

Journal of Fluid Mechanics ◽

10.1017/s0022112088000114 ◽

1988 ◽

Vol 186 ◽

pp. 223-241 ◽

Cited By ~ 25

Author(s):

B. Y. Wang ◽

I. I. Glass

Keyword(s):

Boundary Layer ◽

Flat Plate ◽

Laminar Boundary Layer ◽

Leading Edge ◽

Expansion Method ◽

Boundary Layer Flows ◽

Two Phase ◽

Displacement Thickness ◽

Slip Region ◽

Two Phases

The compressible laminar boundary-layer flows of a dilute gas-particle mixture over a semi-infinite flat plate are investigated analytically. The governing equations are presented in a general form where more reasonable relations for the two-phase interaction and the gas viscosity are included. The detailed flow structures of the gas and particle phases are given in three distinct regions: the large-slip region near the leading edge, the moderate-slip region and the small-slip region far downstream. The asymptotic solutions for the two limiting regions are obtained by using a series-expansion method. The finite-difference solutions along the whole length of the plate are obtained by using implicit four-point and six-point schemes. The results from these two methods are compared and very good agreement is achieved. The characteristic quantities of the boundary layer are calculated and the effects on the flow produced by the particles are discussed. It is found that in the case of laminar boundary-layer flows, the skin friction and wall heat-transfer are higher and the displacement thickness is lower than in the pure-gas case alone. The results indicate that the Stokes-interaction relation is reasonable qualitatively but not correct quantitatively and a relevant non-Stokes relation of the interaction between the two phases should be specified when the particle Reynolds number is higher than unity.

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