scholarly journals Mean flow measurements of heated supersonic slot injection into a high Reynolds number supersonic stream

1990 ◽  
Author(s):  
BENJAMIN SMITH
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Supersonic Stream ◽  
Mean Flow ◽  
Flow Measurements ◽  
High Reynolds

scholarly journals The streamwise turbulence intensity in the intermediate layer of turbulent pipe flow

2015 ◽  
Vol 774 ◽  
pp. 324-341 ◽  
Author(s):  
J. C. Vassilicos ◽  
J.-P. Laval ◽  
J.-M. Foucaut ◽  
M. Stanislas
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Intermediate Layer ◽  
High Reynolds Number ◽  
Logarithmic Derivative ◽  
Turbulent Pipe Flow ◽  
Mean Flow ◽  
The Mean ◽  
High Reynolds

The spectral model of Perryet al. (J. Fluid Mech., vol. 165, 1986, pp. 163–199) predicts that the integral length scale varies very slowly with distance to the wall in the intermediate layer. The only way for the integral length scale’s variation to be more realistic while keeping with the Townsend–Perry attached eddy spectrum is to add a new wavenumber range to the model at wavenumbers smaller than that spectrum. This necessary addition can also account for the high-Reynolds-number outer peak of the turbulent kinetic energy in the intermediate layer. An analytic expression is obtained for this outer peak in agreement with extremely high-Reynolds-number data by Hultmarket al. (Phys. Rev. Lett., vol. 108, 2012, 094501;J. Fluid Mech., vol. 728, 2013, pp. 376–395). Townsend’s (The Structure of Turbulent Shear Flows, 1976, Cambridge University Press) production–dissipation balance and the finding of Dallaset al. (Phys. Rev. E, vol. 80, 2009, 046306) that, in the intermediate layer, the eddy turnover time scales with skin friction velocity and distance to the wall implies that the logarithmic derivative of the mean flow has an outer peak at the same location as the turbulent kinetic energy. This is seen in the data of Hultmarket al. (Phys. Rev. Lett., vol. 108, 2012, 094501;J. Fluid Mech., vol. 728, 2013, pp. 376–395). The same approach also predicts that the logarithmic derivative of the mean flow has a logarithmic decay at distances to the wall larger than the position of the outer peak. This qualitative prediction is also supported by the aforementioned data.

On the theory of unsteady high Reynolds number flow through a circular aperture

1979 ◽  
Vol 366 (1725) ◽  
pp. 205-223 ◽  
Keyword(s):  
Reynolds Number ◽  
Strouhal Number ◽  
High Reynolds Number ◽  
Circular Aperture ◽  
Mean Flow ◽  
Reynolds Number Flow ◽  
Contraction Ratio ◽  
Number Flow ◽  
Flow Through ◽  
High Reynolds

This paper examines the theory of the unsteady motion caused by fluctuations in the driving pressure of a high Reynolds number mean flow through a circular aperture in a thin rigid plate. A theoretical model is proposed which is amenable to exact analytical treatment, and involves the shedding of vorticity from the rim of the aperture. The theory determines the dependence of the Rayleigh conductivity of the aperture on the Strouhal number, and provides quantitative estimates for the rate of dissipation of large scale ordered structures as a result of the generation of turbulence at the apertures in a perforated liner. The limit of zero Strouhal number yields a description of steady high Reynolds number flow, the contraction ratio of the emerging jet being predicted to be equal to the minimum theoretical value of ½. Application is made to the problem of sound trans­mission through a uniformly perforated screen in the presence of a low Mach number bias flow.

scholarly journals Measurements of the Tip Clearance Flow for a High Reynolds Number Axial-Flow Rotor: Part 2 — Detailed Flow Measurements

1994 ◽  
Author(s):  
W. C. Zierke ◽  
K. J. Farrell ◽  
W. A. Straka
Keyword(s):  
Reynolds Number ◽  
Rotor Blade ◽  
High Reynolds Number ◽  
Axial Flow ◽  
Tip Clearance ◽  
Flow Measurements ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Blade Tip ◽  
High Reynolds

A high Reynolds number pump (HIREP) facility has been used to acquire flow measurements in the rotor blade tip clearance region-with blade chord Reynolds numbers of 3,900,000 and 5,500,000. The initial experiment involved rotor blades with varying tip clearances, while a second experiment involved a more detailed investigation of a rotor blade row with a single tip clearance. This paper focuses on detailed flow measurements of the tip leakage vortex. These detailed measurements show the effects of tip clearance size and downstream distance on the structure of the rotor tip leakage vortex. The character of the velocity profile along the vortex core changes from a jet-like profile to a wake-like profile as the tip clearance becomes smaller. These vortex velocity profiles-as well as the levels of unsteadiness-dominate the rotor wake structure in the endwall region. Also, for small clearances, the presence and proximity of the casing endwall affects the roll-up, shape, dissipation, and unsteadiness of the tip leakage vortex. Measurements also show how much circulation is retained by the blade tip and how much is shed into the vortex-a vortex associated with high losses.

Reynolds Number Effects in Wall-Bounded Turbulent Flows

1994 ◽  
Vol 47 (8) ◽  
pp. 307-365 ◽  
Author(s):  
Mohamed Gad-el-Hak ◽  
Promode R. Bandyopadhyay
Keyword(s):  
Reynolds Number ◽  
Coherent Structures ◽  
High Reynolds Number ◽  
Stokes Equations ◽  
Reynolds Numbers ◽  
Mean Flow ◽  
Reynolds Number Effects ◽  
The Mean ◽  
Low Reynolds ◽  
High Reynolds

This paper reviews the state of the art of Reynolds number effects in wall-bounded shear-flow turbulence, with particular emphasis on the canonical zero-pressure-gradient boundary layer and two-dimensional channel flow problems. The Reynolds numbers encountered in many practical situations are typically orders of magnitude higher than those studied computationally or even experimentally. High-Reynolds number research facilities are expensive to build and operate and the few existing are heavily scheduled with mostly developmental work. For wind tunnels, additional complications due to compressibility effects are introduced at high speeds. Full computational simulation of high-Reynolds number flows is beyond the reach of current capabilities. Understanding of turbulence and modeling will continue to play vital roles in the computation of high-Reynolds number practical flows using the Reynolds-averaged Navier-Stokes equations. Since the existing knowledge base, accumulated mostly through physical as well as numerical experiments, is skewed towards the low Reynolds numbers, the key question in such high-Reynolds number modeling as well as in devising novel flow control strategies is: what are the Reynolds number effects on the mean and statistical turbulence quantities and on the organized motions? Since the mean flow review of Coles (1962), the coherent structures, in low-Reynolds number wall-bounded flows, have been reviewed several times. However, the Reynolds number effects on the higher-order statistical turbulence quantities and on the coherent structures have not been reviewed thus far, and there are some unresolved aspects of the effects on even the mean flow at very high Reynolds numbers. Furthermore, a considerable volume of experimental and full-simulation data have been accumulated since 1962. The present article aims at further assimilation of those data, pointing to obvious gaps in the present state of knowledge and highlighting the misunderstood as well as the ill-understood aspects of Reynolds number effects.

Similarity Formulations for Turbulent Boundary Layers at High Reynolds Numbers

2003 ◽  
Author(s):  
Gary J. Kunkel ◽  
Ivan Marusic
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulence Intensity ◽  
High Reynolds Number ◽  
Reynolds Numbers ◽  
Mean Flow ◽  
Mixed Flow ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
New Formulation

Data obtained from the high Reynolds number atmospheric boundary layer are used to analyze existing mean-flow and turbulence intensity similarity formulations. From the results of this analysis a new streamwise turbulence intensity formulation is proposed that is suggested to be applicable across the entire smooth-wall high Reynolds number turbulent boundary layer. The new formulation is also shown to be consistent with the mixed-flow scaling suggested by other studies.

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