Effect of free-stream turbulence on boundary layer transition
Open Access
- 28 July 2014
- journal article
- Published by The Royal Society in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
- Vol. 372 (2020), 20130354
- https://doi.org/10.1098/rsta.2013.0354
Abstract
This paper is concerned with the transition to turbulence in flat plate boundary layers due to moderately high levels of free-stream turbulence. The turbulence is assumed to be generated by an (idealized) grid and matched asymptotic expansions are used to analyse the resulting flow over a finite thickness flat plate located in the downstream region. The characteristic Reynolds number R λ based on the mesh size λ and free-stream velocity is assumed to be large, and the turbulence intensity ε is assumed to be small. The asymptotic flow structure is discussed for the generic case where the turbulence Reynolds number εR λ and the plate thickness and are held fixed (at O (1) and O (λ), respectively) in the limit as and ε →0. But various limiting cases are considered in order to explain the relevant transition mechanisms. It is argued that there are two types of streak-like structures that can play a role in the transition process: (i) those that appear in the downstream region and are generated by streamwise vorticity in upstream flow and (ii) those that are concentrated near the leading edge and are generated by plate normal vorticity in upstream flow. The former are relatively unaffected by leading edge geometry and are usually referred to as Klebanoff modes while the latter are strongly affected by leading edge geometry and are more streamwise vortex-like in appearance.Keywords
This publication has 25 references indexed in Scilit:
- Stability of zero-pressure-gradient boundary layer distorted by unsteady Klebanoff streaksJournal of Fluid Mechanics, 2011
- Boundary-layer transition at high free-stream disturbance levels – beyond Klebanoff modesJournal of Fluid Mechanics, 2008
- Leading-edge effects in bypass transitionJournal of Fluid Mechanics, 2007
- Linear and nonlinear instabilities of a Blasius boundary layer perturbed by streamwise vortices. Part 2. Intermittent instability induced by long-wavelength Klebanoff modesJournal of Fluid Mechanics, 2003
- Detrimental Effects of Almost Immeasurably Small Freestream Nonuniformities Generated by Wind-Tunnel ScreensAIAA Journal, 1998
- The nonlinear evolution of high-frequency resonant-triad waves in an oscillatory Stokes layer at high Reynolds numberJournal of Fluid Mechanics, 1992
- Unsteady disturbances of streaming motions around bodiesJournal of Fluid Mechanics, 1989
- The effect of wind-tunnel screens on nominally two-dimensional boundary layersJournal of Fluid Mechanics, 1965
- The viscous secondary flow ahead of an infinite cylinder in a uniform parallel shear flowJournal of Fluid Mechanics, 1960
- Experimental investigation and analysis of the velocity variations in turbulent flowProceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1934