On the breakdown of boundary layer streaks

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August undefined, 2024

Web7 de abr. de 2024 · Görtler vortex-induced hypersonic boundary layer transition controlled by grooves is investigated using direct numerical simulations and spatial bi-global stability analysis. ... sinuous mode S1 also covers a larger frequency range than the other two secondary instability modes and results in the breakdown of Görtler streaks. http://www.diva-portal.org/smash/record.jsf?pid=diva2:319582

Wall-Normal Variation of Spanwise Streak Spacing in Turbulent …

Web28 de abr. de 2024 · Abstract. A variational framework for the identification and analysis of general nonlinear optimal disturbances in compressible flows is derived. The … WebIn all calculations Reδ = 430 and β = 0.45. - "On the breakdown of boundary layer streaks" Figure 12. Contours of constant absolute values of the streamwise velocity … martin o\u0027donnell golem

On the breakdown of boundary layer streaks - NASA/ADS

Web©2007 The Visualization Society of Japan Journal of Visualization, Vol. 10, No. 2 (2007)217-225 Influence of an Unfavourable Pressure Gradient on the Breakdown of Boundary Layer Streaks Chernoray, V. G.*1, Kozlov, V. V.*2, Lee, I.*3 and Chun, H. H.*3 *1 Applied Mechanics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden. *2 … Web10 de fev. de 2001 · On the breakdown of boundary layer streaks Authors: Luca Brandt KTH Royal Institute of Technology ALESSANDRO BOTTARO Abstract and Figures A … martin o\u0027donnell reddit

Direct Numerical Simulations of Streak Breakdown in Boundary Layers ...

Transition of streamwise streaks in zero-pressure-gradient boundary layers

Web31 de dez. de 2024 · Low-speed streaks in wall-bounded turbulence are the dominant structures in the near-wall turbulent self-sustaining cycle. Existing studies have well characterized their spanwise spacing in the buffer layer and below. Recent studies suggested the existence of these small-scale structures in the high … WebDirect numerical simulations are used to follow the nonlinear evolution of these streaks and to verify secondary instability calculations. The theory is based on a linear Floquet … martin o\u0027donnell and michael salvatoriWeb31 de dez. de 2024 · An analysis is taken on two-dimensional (2D) wall-parallel velocity fields in a smooth-wall turbulent boundary layer with R e τ = 440∼2400, obtained via … martin o\u0027donnell nuig

"Web19 de jul. de 2024 · These streaks induce a flow distortion and lead to a new set of unstable modes. We study the effect of this boundary layer modification using Direct Numerical Simulation (DNS) of a flow at M=6.0 ... " - On the breakdown of boundary layer streaks

On the breakdown of boundary layer streaks

Web5 de jul. de 2024 · Numerical simulations of bypass transition in Blasius boundary layers are presented. The breakdown of streamwise streaks is first considered in the case of the steady, spanwise periodic basic ... Web13 de fev. de 2014 · The base flow is computed in direct simulations of bypass transition. The random nature of the free-stream perturbations causes the formation of a spectrum …

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Webbations developing on boundary layer streamwise streaks. These elongated structures and their breakdown are found to be key factors both in transition in boundary layers … Webof streaks for ﬂat-plate boundary layers was investigated in Refs. 9–11. From these numerical simulations, it was possible to in-vestigate the late stages of the breakdown triggered by the streak instability and identify the relevant ﬂow structures. In the case of sinuous breakdown, the formation of quasi-

WebUsing Floquet theory, the instability of thesestreaks is studied to determine the features of theirbreakdown. The streak critical amplitude, beyond which unstablewaves are excited, … Web4 de out. de 2011 · The discrete modes are non-linearly excited at high harmonics of the inlet perturbation. Adding a Mack second mode, in addition to the vorticity mode, causes even earlier transition, suggesting that, in supersonic flow, unstable discrete modes play a crucial role in breakdown of boundary-layer streaks.

WebDOI: 10.2514/1.j062638 Corpus ID: 257904225; Groove Coating's Effect on Linear and Nonlinear Instability of High-Speed Boundary Layer @article{Zhou2024GrooveCE, title={Groove Coating's Effect on Linear and Nonlinear Instability of High-Speed Boundary Layer}, author={Teng Zhou and Zaijie Liu and Chao Yan}, journal={AIAA Journal}, … WebDOI: 10.2514/1.j062638 Corpus ID: 257904225; Groove Coating's Effect on Linear and Nonlinear Instability of High-Speed Boundary Layer @article{Zhou2024GrooveCE, …

WebHá 1 dia · Thus, the roll-up of the shear layer appears in the second half of the bubble shedding large-scale vortices that keep their identity far downstream at low fst levels. On …

WebThis paper aims at characterizing the bypass transition in boundary layers subject to strong pressure gradient and curvature effects. A series of highly resolved large-eddy … data networking companiesWeb31 de out. de 2008 · Recent theoretical, numerical, and experimental investigations performed at the Department of Mechanics, KTH Stockholm, and the Department of Mechanical Engineering, Eindhoven University of Technology, are reviewed, and new material is presented to clarify the role of the boundary-layer streaks and their … martin o\u0027donnell twitterWebOn the breakdown of boundary layer streaks 35 In the fundamental (γ= 0) case, even (odd) modes are obtained by imposing the conditionp^−k=p^k(p^−k= −p^k). This is … martin o\u0027hara appraiserWeb14 de ago. de 2007 · In a flat plate boundary layer, perturbed with streaks, breakdown occurs due to a secondary instability acting on the streaks. An experimental study using a water channel with static turbulence grid revealed the presence of a sinuous secondary instability mode in the bypass transition process. Five sinuous instabilities are … martin o\u0027donnell \u0026 michael salvatoriWeb13 de fev. de 2001 · Experimental and theoretical investigation of the nonmodal growth of steady streaks in a flat plate boundary layer. Physics of Fluids, Vol. 16, Issue. 10, p. 3627. CrossRef martin o\u0027grady clipperWebBreakdown of boundary layer streaks is studied experimentally and compared at zero and adverse (positive) streamwise pressure gradients on a wing under fully controlled experimental conditions. The varicose mode of streak breakdown is found to be a ... martin o\u0027donnell haloWeb30 de mai. de 2024 · In this study direct numerical simulation is employed to investigate the effects of various parameters on the flow control capabilities of narrowly spaced streaks in a boundary layer at M ∞ = 2.0. martin o\u0027halloran