Results 281 to 290 of about 117,422 (348)

Coherent Structures in Transitional and Turbulent Free Shear Flows

Annual Review of Fluid Mechanics, 1989
The development of a quantitative understanding of large-scale coherent structures in shear flows has led to the recognition of their evolutionary features and 'rules' of nonlinear interaction among each other. These determinations, in conjunction with the study of fine-grained turbulence and mean motion, constitute a general view of hydrodynamical ...
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SCALAR TRANSPORT AND MIXING IN TURBULENT STRATIFIED SHEAR FLOW

Proceeding of First Symposium on Turbulence and Shear Flow Phenomena, 1999
In this study, the evolution of the velocity field and scalar concentration fields in stably stratified shear flow is studied using direct numerical simulations. Two cases with vertical mean shear and horizontal mean shear are compared. In both cases, the growth of the turbulent kinetic energy weakens as the Richardson number is increased. However, the
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Convective and Shear Flow Turbulence with Rotation

1992
As an introduction to this section we present an extension of the discussion of Mory [1] to include a case of more general geophysical significance, where the source of the initial turbulent motion is a natural one rather than the rather artificial case of turbulence generated by an oscillating grid.
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Fractals, Chaos, and Intermittency in Turbulent Shear Flows

Chaos in Heat Transfer and Fluid Dynamics, 1994
Abstract The fractal dimensions for fine scale turbulent velocity fields are estimated in two different ways: (1) from the Kolmogorov constant, μ, and (2) from the kurtosis of the velocity derivative. The fractal dimensions, D, are estimated to be in the range 2.45 ≤ D ≤ 2.73 which is comparable to previous investigations.
George D. Catalano, Julie A. Mathis, Keun S. Chang   +2 more
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Flow Visualization of Karman Vortex in Shear and Turbulent Flow

1992
Karman vortex velocimeter and flowmeter by use of laser diode have been developed in our laboratory 1).2). However the effects from such as shear flow, turbulent flow, channel wall and etc. are little known. In fact, the frequency of the Karman vortex in the shear flow which was measured by the method developed in our study was lower than that of the ...
S. Saito, M. Hashimoto, Y. Higuchi
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Turbulence and shear stress measurements in hypersonic flow

16th Aerodynamic Ground Testing Conference, 1990
An assessment has been made of the potential for hot wire and laser anemometer measurements of turbulent fluctuations in hypersonic flow fields. The results of laser velocimeter experiments conducted in two hypersonic wind tunnels are reported and comparisons made with previous hot wire turbulence measurements.
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Interaction of monopoles, dipoles, and turbulence with a shear flow

Physics of Fluids, 2016
Direct numerical simulations have been conducted to examine the evolution of eddies in the presence of large-scale shear flows. The numerical experiments consist of initial-value-problems in which monopolar and dipolar vortices as well as driven turbulence are superposed on a plane Couette or Poiseuille flow in a periodic two-dimensional channel.
V. H. Marques Rosas Fernandes, L. P. J. Kamp, G. J. F. van Heijst, H. J. H. Clercx   +3 more
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Turbulence and mixing in a stratified shear flow

Geophysical & Astrophysical Fluid Dynamics, 1991
Abstract The characteristics of turbulence in the upper mixed layer and the nature of the sheared density interface of a two-fluid system, with a driven upper layer and a stagnant lower layer, were studied experimentally. The experiments were performed in a recirculating water channel and the mean flow in the upper layer was generated using a disk pump.
P. W. Stephenson, H. J. S. Fernando
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Large Scale Motions and Shear Stress Fluctuations in Turbulent Shear Flow

Volume 1A: Symposia, Part 2, 2015
We simultaneously measured the flow field and wall shear stress in a straight pipe and behind an orifice by means of particle image velocimetry (PIV) and the limiting diffusion current technique (LDCT), respectively[1]. The spatio-temporal correlation coefficients of the local vertical velocity and the shear stress fluctuations are presented, and the ...
Hinori Ito, Tatsuya Tsuneyoshi, Shan Feng, Takahiro Ito, Yoshiyuki Tsuji, Yuya Hideki   +5 more
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Vortical Structures in Transitional and Turbulent Shear Flows

2006
While in Chap. 10 we focused on the instability and breakdown of axial vortices, in this chapter we turn to the instability of shear layers, both free and wall-bounded. Unlike axial vortices, however, shear-flow transition from laminar to turbulent and fully developed turbulent shear flows have been the main field of turbulence and investigated much ...
Jie-Zhi Wu, Hui-Yang Ma, Ming-De Zhou
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