High-Speed Boundary Layer Instability on a Flat Plate at Angle of Attack with Porous Walls

2022 ◽  
Author(s):  
Samantha A. Miller ◽  
Derek Mamrol ◽  
Joel J. Redmond ◽  
Karl Jantze ◽  
Carlo Scalo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
High Speed ◽  
Angle Of Attack ◽  
Boundary Layer Instability ◽  
Porous Walls

Large-eddy simulation of transition to turbulence in a boundary layer developing spatially over a flat plate

1996 ◽  
Vol 326 ◽  
pp. 1-36 ◽  
Author(s):  
FréDÉRic Ducros, Pierre Comte ◽  
Marcel Lesieur
Keyword(s):  
Boundary Layer ◽  
Structure Function ◽  
Flat Plate ◽  
High Speed ◽  
Large Scale ◽  
Phase Speed ◽  
Transition To Turbulence ◽  
Order Structure ◽  
Spanwise Direction ◽  
Large Eddy

It is well known that subgrid models such as Smagorinsky's cannot be used for the spatially growing simulation of the transition to turbulence of flat-plate boundary layers, unless large-amplitude perturbations are introduced at the upstream boundary: they are over-dissipative, and the flow simulated remains laminar. This is also the case for the structure-function model (SF) of Métais & Lesieur (1992). In the present paper we present a sequel to this model, the filtered-structure-function (FSF) model. It consists of removing the large-scale fluctuations of the field before computing its second-order structure function. Analytical arguments confirm the superiority of the FSF model over the SF model for large-eddy simulations of weakly unstable transitional flows. The FSF model is therefore used for the simulation of a quasi-incompressible (M∞ = 0.5) boundary layer developing spatially over an adiabatic flat plate, with a low level of upstream forcing. With the minimal resolution 650 × 32 × 20 grid points covering a range of streamwise Reynolds numbers Rex1 ε [3.4 × 105, 1.1 × 106], transition is obtained for 80 hours of time-processing on a CRAY 2 (whereas DNS of the whole transition takes about ten times longer). Statistics of the LES are found to be in acceptable agreement with experiments and empirical laws, in the laminar, transitional and turbulent parts of the domain. The dynamics of low-pressure and high-vorticity distributions is examined during transition, with particular emphasis on the neighbourhood of the critical layer (defined here as the height of the fluid travelling at a speed equal to the phase speed of the incoming Tollmien–Schlichting waves). Evidence is given that a subharmonic-type secondary instability grows, followed by a purely spanwise (i.e. time-independent) mode which yields peak-and-valley splitting and transition to turbulence. In the turbulent region, flow visualizations and local instantaneous profiles are provided. They confirm the presence of low- and high-speed streaks at the wall, weak hairpins stretched by the flow and bursting events. It is found that most of the vorticity is produced in the spanwise direction, at the wall, below the high-speed streaks. Isosurfaces of eddy viscosity confirm that the FSF model does not perturb transition much, and acts mostly in the vicinity of the hairpins.

Effects of Passive Porous Walls on Boundary-Layer Instability

AIAA Journal ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 597-604 ◽  
Author(s):  
Peter W. Carpenter ◽  
Lee J. Porter
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Instability ◽  
Porous Walls

On the generation of steady streamwise streaks in flat-plate boundary layers

2012 ◽  
Vol 698 ◽  
pp. 211-234 ◽  
Author(s):  
Jens H. M. Fransson ◽  
Alessandro Talamelli
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
High Speed ◽  
Control Method ◽  
Plate Boundary ◽  
High Amplitude ◽  
Base Flow ◽  
Stream Velocity ◽  
Bypass Transition ◽  
Streamwise Streaks

AbstractA study on the generation and development of high-amplitude steady streamwise streaks in a flat-plate boundary layer is presented. High-amplitude streamwise streaks are naturally present in many bypass transition scenarios, where they play a fundamental role in the breakdown to turbulence process. On the other hand, recent experiments and numerical simulations have shown that stable laminar streamwise streaks of alternating low and high speed are also capable of stabilizing the growth of Tollmien–Schlichting waves as well as localized disturbances and to delay transition. The larger the streak amplitude is, for a prescribed spanwise periodicity of the streaks, the stronger is the stabilizing mechanism. Previous experiments have shown that streaks of amplitudes up to 12 % of the free stream velocity can be generated by means of cylindrical roughness elements. Here we explore the possibility of generating streaks of much larger amplitude by using a row of miniature vortex generators (MVGs) similar to those used in the past to delay or even prevent boundary layer separation. In particular, we present a boundary layer experiment where streak amplitudes exceeding 30 % have been produced without having any secondary instability acting on them. Furthermore, the associated drag with the streaky base flow is quantified, and it is demonstrated that the streaks can be reinforced by placing a second array of MVGs downstream of the first one. In this way it is possible to make the control more persistent in the downstream direction. It must be pointed out that the use of MVGs opens also the possibility to set up a control method that acts twofold in the sense that both transition and separation are delayed or even prevented.

Simulation of blunt-fin-induced shock-wave and turbulent boundary-layer interaction

1985 ◽  
Vol 154 ◽  
pp. 163-185 ◽  
Author(s):  
Ching-Mao Hung ◽  
Pieter G. Buning
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Flat Plate ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Layer Interaction ◽  
Boundary Layer Interaction

The Reynolds-averaged Navier–Stokes equations are solved numerically for supersonic flow over a blunt fin mounted on a flat plate. The fin shock causes the boundary layer to separate, which results in a complicated, three-dimensional shock-wave and boundary-layer interaction. The computed results are in good agreement with the mean static pressure measured on the fin and the flat plate. The main features, such as peak pressure on the fin leading edge and a double peak on the plate, are predicted well. The role of the horseshoe vortex is discussed. This vortex leads to the development of high-speed flow and, hence, low-pressure regions on the fin and the plate. Different thicknesses of the incoming boundary layer have been studied. Varying the thicknesses by an order of magnitude shows that the size of the horseshoe vortex and, therefore, the spatial extent of the interaction are dominated by inviscid flow and only weakly dependent on the Reynolds number. Coloured graphics are used to show details of the interaction flow field.

Effects of passive porous walls on boundary-layer instability

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 597-604 ◽  
Author(s):  
Peter W. Carpenter ◽  
Lee J. Porter
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Instability ◽  
Porous Walls

An Experimental Investigation on the Characteristics of Turbulent Boundary Layer Flows Over a Dimpled Surface

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Wenwu Zhou ◽  
Yu Rao ◽  
Hui Hu
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Turbulent Boundary Layer ◽  
Flat Plate ◽  
Surface Pressure ◽  
High Speed ◽  
Boundary Layer Flows ◽  
Piv Measurement ◽  
Measurement Results ◽  
Flow Features

An experimental investigation was conducted to quantify the characteristics of the turbulent boundary layer flows over a dimpled surface in comparison to those over a conventional flat plate. In addition to measuring surface pressure distributions to determine the friction factors of the test plates and to map the surface pressure inside the dimple cavity, a high-resolution digital particle image velocimetry (PIV) system was used to achieve detailed flow field measurements to quantify the characteristics of the turbulent boundary layer flows over the test plates and the evolution of the unsteady vortex structures inside the dimple cavity at the middle of the dimpled test plate. It was found that the friction factor of the dimpled plate would be about 30–80% higher than that of the flat plate, depending on the Reynolds number of the test cases. In comparison with those over a conventional flat surface, the flow characteristics of the turbulent boundary layer flows over the dimpled surface were found to be much more complicated with much stronger near-wall Reynolds stress and higher turbulence kinetic energy (TKE) levels, especially in the region near the back rims of the dimples. Many interesting flow features over the dimple surface, such as the separation of oncoming boundary layer flow from the dimpled surface when passing over the dimple front rim, the formation and periodic shedding of unsteady Kelvin–Helmholtz vortices in the shear layer over the dimple, the impingement of the high-speed incoming flow onto the back rim of the dimple, and the subsequent generation of strong upwash flow in the boundary flow to promote the turbulent mixing over the dimpled surface, were revealed clearly and quantitatively from the PIV measurement results. The quantitative measurement results are believed to be the first of its nature, which depict a vivid picture about the unique flow features over dimpled surfaces and their correlations with the enhanced heat transfer performance reported in previous studies.

High-Speed Boundary-Layer Instability: Old Terminology and a New Framework

AIAA Journal ◽  
2011 ◽  
Vol 49 (8) ◽  
pp. 1647-1657 ◽  
Author(s):  
Alexander Fedorov ◽  
Anatoli Tumin
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Boundary Layer Instability ◽  
New Framework

An appraisal of ‘flat plate’ closure for the approximate solution of boundary layer problems

1987 ◽  
Vol 91 (908) ◽  
pp. 373-389
Author(s):  
D. I. A. Poll ◽  
C. M. Hellon
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mach Number ◽  
Flat Plate ◽  
High Speed ◽  
Compressible Flows ◽  
Incompressible Flows ◽  
Similarity Solutions ◽  
Laminar Flows ◽  
Reynolds Analogy

SummaryThe usefulness of zero pressure gradient, flat plate closure relations in providing approximate solutions for the boundary layer momentum and energy integral equations is examined. Expressions are obtained for skin friction, surface heat transfer rate and local Reynolds analogy factor under general compressible flow conditions. For laminar flows the predictions are compared with well known similarity solutions, with some exact solutions for non-similar flows and with experimental heat transfer data for high speed flow over a blunt cone. Consideration is also given to situations in which the surface temperature is a function of position. For turbulent flow situations comparisons are made with experimental data obtained from two-dimensional and axi-symmetric tests. Conditions vary from low Mach number incompressible flows through to high Mach number compressible flows with highly cooled walls. Some comparisons are also made with other prediction techniques.

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