Incompressible Jet Mixing in Converging-Diverging Axisymmetric Ducts

1967 ◽  
Vol 89 (1) ◽  
pp. 210-220 ◽  
Author(s):  
P. G. Hill
Keyword(s):  
Reynolds Number ◽  
Sole Source ◽  
Turbulent Jet ◽  
Velocity Shear ◽  
Jet Mixing ◽  
Similarity Relations ◽  
Turbulent Reynolds Number ◽  
Turbulent Jet Flow ◽  
Axisymmetric Tube ◽  
Good Agreement

A test has been made of the constant turbulent Reynolds number hypothesis for a turbulent jet flow in a converging-diverging axisymmetric tube. Using the free turbulent jet as the sole source of data for evaluation of the Reynolds number, and velocity shear distributions, the general ducted flow was predicted with the aid of appropriate similarity relations. Calculated results are compared with the extensive and consistent data of Helmbold; good agreement is observed. It is found that the methods of calculation employed can be considerably simplified without large effect on the calculated results. The existence and extent of zones of recirculation are also discussed.

Simultaneous Velocity and Concentration Measurements of a Turbulent Jet Mixing Flow

2002 ◽  
Vol 972 (1) ◽  
pp. 254-259 ◽  
Author(s):  
HUI HU ◽  
TETSUO SAGA ◽  
TOSHIO KOBAYASHI ◽  
NOBUYUKI TANIGUCHI
Keyword(s):  
Turbulent Jet ◽  
Jet Mixing ◽  
Concentration Measurements

scholarly journals Effects of Turbulent Reynolds Number on the Performance of Algebraic Flame Surface Density Models for Large Eddy Simulation in the Thin Reaction Zones Regime: A Direct Numerical Simulation Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mohit Katragadda ◽  
Nilanjan Chakraborty ◽  
R. S. Cant
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Fractal Dimension ◽  
Direct Numerical Simulation ◽  
Surface Density ◽  
Flame Surface ◽  
Algebraic Models ◽  
Flame Surface Density ◽  
Turbulent Reynolds Number ◽  
Reaction Zones

A direct numerical simulation (DNS) database of freely propagating statistically planar turbulent premixed flames with a range of different turbulent Reynolds numbers has been used to assess the performance of algebraic flame surface density (FSD) models based on a fractal representation of the flame wrinkling factor. The turbulent Reynolds number Rethas been varied by modifying the Karlovitz number Ka and the Damköhler number Da independently of each other in such a way that the flames remain within the thin reaction zones regime. It has been found that the turbulent Reynolds number and the Karlovitz number both have a significant influence on the fractal dimension, which is found to increase with increasing Retand Ka before reaching an asymptotic value for large values of Retand Ka. A parameterisation of the fractal dimension is presented in which the effects of the Reynolds and the Karlovitz numbers are explicitly taken into account. By contrast, the inner cut-off scale normalised by the Zel’dovich flame thicknessηi/δzdoes not exhibit any significant dependence on Retfor the cases considered here. The performance of several algebraic FSD models has been assessed based on various criteria. Most of the algebraic models show a deterioration in performance with increasing the LES filter width.

scholarly journals Feasibility study of power generation using a turbine mounted in aircraft wing

2018 ◽  
Vol 7 (2-1) ◽  
pp. 433
Author(s):  
K. Sri Vamsi Krishna ◽  
Shiva Prasad ◽  
R. Sabari Vihar ◽  
K. Babitha ◽  
K Veeranjaneyulu ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Power Systems ◽  
Free Stream ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Aircraft Wing ◽  
Aerodynamic Efficiency ◽  
Turbulent Reynolds Number ◽  
Main Motive ◽  
Emergency Power

The main objective of this study is to increase the aerodynamic efficiency of turbine mounted novel wing. The main motive behind this work is to reduce the drag by attaining the positive velocity gradient and generate power by converting the stagnation pressure which also acts as emergency power source. By using the energy source of free stream air, Mechanical energy is converted into electrical energy. The obtained power is presented in terms of voltage generated at various angles of attack with different Reynolds number. Experimental analysis is carried out for NACA4415 airfoil at various angles with respect to free stream ranging from 0deg to 30deg from laminar to turbulent Reynolds number. The results were obtained using the research tunnel at IARE aerodynamic facility center. The aerodynamic advantage of this design in terms of voltage is 9.5 V at 35m/s which can be utilized for the aircraft on board power systems.

scholarly journals The Turbulent Jet from a Series of Holes in Line

1964 ◽  
Vol 15 (1) ◽  
pp. 1-28 ◽  
Author(s):  
R. Knystautas
Keyword(s):  
Jet Flow ◽  
Turbulent Jet ◽  
Two Dimensional ◽  
Turbulent Jet Flow ◽  
Similar Density

SummaryThe possibility of obtaining two-dimensional turbulent jet flow from a series of closely-spaced uniform holes in line has been investigated both theoretically and experimentally. The case studied was that of a jet discharging into still fluid of similar density at incompressible speeds. Such a quasi-two-dimensional jet is a particular example of a multiple-interfering jet group.

Low-Reynolds-number flow around an oscillating circular cylinder at low Keulegan–Carpenter numbers

1998 ◽  
Vol 360 ◽  
pp. 249-271 ◽  
Author(s):  
H. DÜTSCH ◽  
F. DURST ◽  
S. BECKER ◽  
H. LIENHART
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Time Step ◽  
Time Resolved ◽  
Reynolds Number Flow ◽  
Line Force ◽  
Number Flow ◽  
Weakly Stable ◽  
Fluid Behaviour ◽  
Good Agreement

Time-averaged LDA measurements and time-resolved numerical flow predictions were performed to investigate the laminar flow induced by the harmonic in-line oscillation of a circular cylinder in water at rest. The key parameters, Reynolds number Re and Keulegan–Carpenter number KC, were varied to study three parameter combinations in detail. Good agreement was observed for Re=100 and KC=5 between measurements and predictions comparing phase-averaged velocity vectors. For Re=200 and KC=10 weakly stable and non-periodic flow patterns occurred, which made repeatable time-averaged measurements impossible. Nevertheless, the experimentally visualized vortex dynamics was reproduced by the two-dimensional computations. For the third combination, Re=210 and KC=6, which refers to a totally different flow regime, the computations again resulted in the correct fluid behaviour. Applying the widely used model of Morison et al. (1950) to the computed in-line force history, the drag and the added-mass coefficients were calculated and compared for different grid levels and time steps. Using these to reproduce the force functions revealed deviations from those originally computed as already noted in previous studies. They were found to be much higher than the deviations for the coarsest computational grid or the largest time step. The comparison of several in-line force coefficients with results obtained experimentally by Kühtz (1996) for β=35 confirmed that force predictions could also be reliably obtained by the computations.

scholarly journals NUMERICAL AND EXPERIMENTAL MODELING OF INTERACTION BETWEEN A TURBULENT JET FLOW AND AN INLET

2000 ◽  
Vol 22 (1) ◽  
pp. 29-38
Author(s):  
H. D. Lien ◽  
I. S. Antonov
Keyword(s):  
Convective Flow ◽  
Integral Method ◽  
Natural Experiment ◽  
Present Model ◽  
Turbulent Jet ◽  
Sources Of Pollution ◽  
Two Component ◽  
Local Sources ◽  
Turbulent Jet Flow ◽  
Harmful Substances

In ventilation devices to get rid of harmful substances out of workingplaces, we use sucking devices. The local sources of pollution are evacuated by them. Abasic element when creating the model of sucking device is: the source of harmful substancesis discussed as a rising convective flow, which is ejected out of sucking spectrum,created by a sucking apparatus. In the present work, the flow is a whole one with variablequantity of motion and kinetic energy along it's length. The change in those twoparameters is caused by and is in dependent function of the inlet spectrum. There hasbeen discussed a two-component flow of air and gas in ventilation devices. A two-velocityscheme of flow is used to realise the numerical method. An integral method of investigationis used, based on the conditions of conservation of mass contents, quantity of motion andkinetic energy. It's been accepted that quantity of motion and energy change in functionof inlet action. A comparison of numerical results and natural experiment are made fortwo conditions: full suck and not full suck. Conclusion is that the present model is preciseand can be unset for engineering calculations.

The thermal signature of a low Reynolds number submerged turbulent jet impacting a free surface

2008 ◽  
Vol 20 (11) ◽  
pp. 115102 ◽  
Author(s):  
K. Peter Judd ◽  
Geoffrey B. Smith ◽  
Robert A. Handler ◽  
Ankur Sisodia
Keyword(s):  
Reynolds Number ◽  
Free Surface ◽  
Low Reynolds Number ◽  
Turbulent Jet ◽  
Low Reynolds ◽  
Thermal Signature
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