Turbulent Flow Characteristics of an Impinging Plane Jet
Author : Peter John Russell
Publisher :
Page : pages
File Size : 27,17 MB
Release : 1970
Category :
ISBN :
Author : Peter John Russell
Publisher :
Page : pages
File Size : 27,17 MB
Release : 1970
Category :
ISBN :
Author : J. J. Schauer
Publisher :
Page : 200 pages
File Size : 29,48 MB
Release : 1963
Category : Aerodynamic heating
ISBN :
Author : John Joseph Schauer
Publisher :
Page : 116 pages
File Size : 33,21 MB
Release : 1963
Category : Jets
ISBN :
Author : Genrikh Naumovich Abramovich
Publisher : Mit Press
Page : 671 pages
File Size : 29,30 MB
Release : 1963
Category : Technology & Engineering
ISBN : 9780262010085
The author's first monograph on turbulent jets, in 1936, dealt solely with a free submerged jet. Since that time, the theory of the turbulent jet has been developed in many published works both in the USSR and abroad: it has been enriched with a large amount of experimental material and has been applied in many new fields of engineering. In the last 10 years very substantial progress has been made, and it has now become possible to go beyond the free submerged jet and to solve the problem of a jet in a stream of fluid, to take into account the interaction between the jet and solid walls, to ascertain the relationship between the contour of the jet and the ratio of its density to the density of the surrounding medium, and to establish the characteristic features of a supersonic jet. This monograph contains the results of further research by the author and his colleagues, as well as a critical reappraisal of the more important theoretical and experimental data published by other investigators. The first section deals with the theory of a turbulent jet of incompressible fluid. It gives a systematic analysis of numerous experimental data on velocity profiles, temperature, and the impurity concentration, as well as the outlines of the turbulent mixing lone. The second section sets forth the theory of turbulent gas jets, including strongly preheated and supersonic jets. The theory of free turbulence in a gas, suitable in principle for any degree of compressibility, is revised, and the equations are derived for motion and heat exchange in the boundary layer of a jet at very high temperature. The third section solves several problems of the spreading of jets in finite and semifinite space, and the fourth section describes various applications of the theory of jets, many of which are reported for the first time or have been significantly revised.
Author : Young-Min Shim
Publisher :
Page : 119 pages
File Size : 47,55 MB
Release : 2012
Category : Cylinders
ISBN :
An experimental study was performed for the developing structural characteristics of a plane jet at Re = 3,000. The velocity field measurements were made using particle image velocimetry (PIV) in a water jet facility. The proper orthogonal decomposition (POD) method was applied to the two-dimensional PIV data to reveal large-scale vortical structures in the jet flow. The symmetrical counter-rotating vortices that have been discussed in previous jet studies were confirmed in the initial region. It was found that these vortices were generated as a result of the first vortex merging at the subharmonic sideband frequency, f0 ±fc /2, where f0 was the initial jet shear instability frequency and was the jet column frequency. Moving downstream, their characteristic frequency evolved into f0/2-3fc /4 through nonlinear interaction. In the interaction region, symmetrical vortices were gradually displaced with each other in the streamwise direction and antisymmetrical vortices were eventually formed. The negative correlation between streamwise velocity fluctuations at two points on opposite sides of the jet centreline was caused by the passage of vortical structures. An experimental study was also conducted for the structural characteristics of an impinging jet on a circular cylinder for two cases D/h = 0.5 and 1 where D was the diameter of the cylinder and h was the nozzle height. The mean and turbulent flow fields of the D/h = 0.5 case appeared to be the replica of the wake behind the circular cylinder in cross flow. In contrast, those of the D/h = 1 case showed significantly different features. The alternate vortex shedding and the symmetrical secondary vortices were commonly found in the results of both cases, but the former was pronounced for D/h = 0.5 and the latter was dominant for D/h = 1. The characteristic frequency of the free jet vortices was found to be f0/2 -1/5(f0/2) ; namely, the subharmonic of the initial jet shear layer instability f0 was modulated at 1/5(f0/2. This modulating frequency arose from the upstream propagation of perturbation at the cylinder surface by the impinging free jet vortices. As the free jet vortices approached the cylinder, thin vortex layers were generated due to the adverse pressure gradient. The separation of these vortex layers led to shedding of the symmetrical secondary vortices. The presence of symmetrical secondary vortices instead of alternate vortex shedding suggests a strong influence of the symmetrically arranged free jet vortices. For D/h = 0.5, the free jet vortices and the symmetrical secondary vortices interacted convectively as they moved downstream parallel to the centreline of the flow field. As a result, the alternate vortex shedding was formed and the corresponding frequency spectra exhibited multiple peaks at discrete frequencies. For D/h = 1, the symmetrical secondary vortices were convected downstream without a direct interaction with the free jet vortices due to the deflection of the free jet vortices away from the cylinder. The alternate vortex shedding was also observed but its characteristic frequency was much lower than that of the D/h = 0.5 case and was the same as the difference between the characteristic frequencies of the free jet vortices and the secondary vortices. According to the previous heat transfer studies for impinging jet on a circular cylinder, the averaged Nusselt number was found to increase with decreasing curvature ratio D/h. Therefore, it is possible to postulate that alternate vortex shedding is responsible for higher heat transfer and is thus a more efficient flow structure than induced symmetrical secondary vortices only.
Author : James W. Gauntner
Publisher :
Page : 52 pages
File Size : 47,40 MB
Release : 1970
Category : Heat
ISBN :
Flow characteristics of single jets impinging on flat surfaces have been studied by many investigators. The results of some of the numerous studies are summarized herein. Suggested methods for determining velocities and pressures on which to base heat-transfer correlations for use in impingement cooling design are presented.
Author : Touraj Davanipour
Publisher :
Page : 36 pages
File Size : 25,80 MB
Release : 1975
Category : Jets
ISBN :
Author : Peter Hrycak
Publisher :
Page : 32 pages
File Size : 23,69 MB
Release : 1970
Category :
ISBN :
Author : N. Rajaratnam
Publisher : Elsevier
Page : 315 pages
File Size : 36,79 MB
Release : 1976-01-01
Category : Science
ISBN : 0080869963
Turbulent Jets
Author : James W. Gauntner
Publisher :
Page : 43 pages
File Size : 10,32 MB
Release : 1970
Category : Heat
ISBN :