Journal ArticleDOI
The turbulence structure of a highly curved mixing layer
Ian P. Castro,Peter Bradshaw +1 more
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In this paper, extensive one-point measurements have been made of the turbulence structure of the mixing layer bounding a normally impinging plane jet with an irrotational core, and the most striking feature is that the return is not monotonic: after decreasing in the region of stabilizing curvature, the Reynolds stresses, triple products, energy dissipation rate and other turbulence quantities overshoot the plane-layer values before finally decreasing.Abstract:
As part of a general investigation of complex turbulent flows, extensive one-point measurements have been made of the turbulence structure of the mixing layer bounding a normally impinging plane jet with an irrotational core. The ratio of shear-layer thickness to streamline radius of curvature reaches a maximum of about 0.2, the sense of the curvature being stabilizing. Downstream of the impingement region the shear layer returns asymptotically to being a classical plane mixing layer. The most striking feature of the results is that the return is not monotonic: after decreasing in the region of stabilizing curvature, the Reynolds stresses, triple products, energy dissipation rate and other turbulence quantities overshoot the plane-layer values before finally decreasing. Some conclusions are drawn about the nature of the turbulent transport of Reynolds stress, and about the representation of this and other processes in calculation methods for complex turbulent flows. An incidental result of the work is a comprehensive set of measurements in a plane mixing layer.read more
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Journal ArticleDOI
A Review of Research on Subsonic Turbulent Flow Reattachment
John K. Eaton,James P. Johnston +1 more
TL;DR: A review of the available data for turbulent flows over backward-facing steps, including some new data of our own and other previously unpublished data, is presented in this paper, where the authors suggest several areas of research that could lead to improvements in our ability to predict flows with separation bubbles.
Journal ArticleDOI
Turbulence models and their applications to the prediction of internal flows: a review
TL;DR: In this paper, a brief account of various turbulence models employed in the computation of turbulent flows, and evaluation of the application of these models to selected internal flow configurations is presented. But, the main conclusions of this analysis are: (1) the k-epsilon model is used in a majority of all the two-dimensional flow calculations reported in the literature; (2) modified forms of the K-Epsilon model improve the performance for flows with streamline curvature and heat transfer; (3) for flow with swirl, the algebraic stress model performs rather
Journal ArticleDOI
Effects of the initial condition on the axisymmetric free shear layer: Effects of the initial momentum thickness
A. K. M. F. Hussain,M. F. Zedan +1 more
TL;DR: In this article, the effects of the initial condition on the characteristic measures of an axisymmetric air free shear layer were investigated experimentally, and it was found that the spread rate, similarity parameter, and peak turbulent intensity in the self-preserving region are essentially independent of Rϑe, but dependent on whether the initial boundary layer is laminar or tripped (turbulent).
Journal ArticleDOI
The structure of a turbulent shear layer bounding a separation region
Ian P. Castro,A. Haque +1 more
TL;DR: In this article, the authors used pulsed-wire anemometry to measure the Reynolds number in the separated shear layer behind a flat plate normal to an airflow, showing that the normal stresses all rise monotonically as reattachment is approached, are always considerably higher than the plane layer values and develop in quite different ways.
Journal ArticleDOI
New Advanced k-w Turbulence Model for High-Lift Aerodynamics
TL;DR: In this article, a new k-ω turbulence model based on explicit algebraic Reynolds-stress modeling is presented, which is especially designed for the requirements typical in high-lift aerodynamics.
References
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Journal ArticleDOI
Progress in the development of a Reynolds-stress turbulence closure
TL;DR: In this article, the authors developed a model of turbulence in which the Reynolds stresses are determined from the solution of transport equations for these variables and for the turbulence energy dissipation rate E. Particular attention is given to the approximation of the pressure-strain correlations; the forms adopted appear to give reasonably satisfactory partitioning of the stresses both near walls and in free shear flows.
Journal ArticleDOI
On density effects and large structure in turbulent mixing layers
Garry L. Brown,Anatol Roshko +1 more
TL;DR: In this article, Spark shadow pictures and measurements of density fluctuations suggest that turbulent mixing and entrainment is a process of entanglement on the scale of the large structures; some statistical properties of the latter are used to obtain an estimate of entrainedment rates, and large changes of the density ratio across the mixing layer were found to have a relatively small effect on the spreading angle.
Journal ArticleDOI
Vortex pairing : the mechanism of turbulent mixing-layer growth at moderate Reynolds number
C. D. Winant,F. K. Browand +1 more
TL;DR: A mixing layer is formed by bringing two streams of water, moving at different velocities, together in a lucite-walled channel as mentioned in this paper, where dye is injected between the two streams just before they are brought together, marking the vorticitycarrying fluid.
Book
An introduction to turbulence and its measurement
TL;DR: This dissertation aims to provide a history of web exceptionalism from 1989 to 2002, a period chosen in order to explore its roots as well as specific cases up to and including the year in which descriptions of “Web 2.0” began to circulate.
Journal ArticleDOI
Turbulence spectra from a tidal channel
TL;DR: In this article, the authors used a hot film flowmeter in the sea and presented experimental measurements of the downstream component of turbulent velocity in a tidal channel, where the Reynolds number of the flow is about 108 and the scale of the turbulence is so large that a ship is carried about to a considerable extent by the energy-containing eddies.