Numerical Study of Two-Dimensional Co-Flowing Turbulent Jets

2007 ◽  
Author(s):  
Tarek Abdel-Salam
Keyword(s):  
Numerical Analysis ◽  
Initial Velocity ◽  
Numerical Study ◽  
Turbulent Jets ◽  
Reynolds Numbers ◽  
Two Dimensional ◽  
Structured Grids ◽  
Study Results ◽  
Flow Geometry ◽  
Jet Velocities

The present study reports numerical analysis of turbulent jets. This study investigates the effect of initial jet velocity on the location of the merging and combining points of two dimensional co-flowing turbulent jets. Flow geometry under consideration is three co-flowing rectangular jets. Effects of inner jet and outer jets exit velocities are investigated. Numerical results are obtained with a finite volume CFD code. Turbulence is treated with a two equation k-e model. Different jet velocities have been examined corresponding to Reynolds numbers of 2,000 to 35,000. Structured grids are used in the present study. Results show that the initial velocity of the inner jet has significant effect on the merging and combining points.

Numerical Study of Two-Dimensional Turbulent Jets

2006 ◽  
Author(s):  
Tarek Abdel-Salam ◽  
Gerald Micklow ◽  
Keith Williamson
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Numerical Study ◽  
Turbulent Jets ◽  
Parallel Plane ◽  
Two Dimensional ◽  
Reattachment Point ◽  
Wall Angle ◽  
Plane Jets ◽  
Turbulent Plane

The current study reports numerical analysis of turbulent jets. Effects of various parameters on the characteristics of two-dimensional turbulent plane parallel and offset jets are investigated. The emphasis is put on the effect of the wall angle and nozzle width on the location merging and the combining points. The flowfield under consideration are two-parallel plane jets and offset jets issued from plane wall. Four angles and three values of the nozzle width are used. Also, different values of Reynolds number between 9000 and 39000 have been examined. It is noted that the wall angle and the nozzle width linearly affect the location of the merging and the combining points, while Reynolds number plays no role in their location. The effect of the wall angle on the reattachment point is found to be non linear.

Numerical Study of Two-Dimensional Turbulent Jets Issued from Inclined Wall

2008 ◽  
Vol 35 (1) ◽  
pp. 60-75 ◽  
Author(s):  
Tarek Abdel-Salam ◽  
Gerald Micklow ◽  
Keith Williamson
Keyword(s):  
Numerical Study ◽  
Turbulent Jets ◽  
Two Dimensional

Numerical Study of Two-Dimensional Circular Cylinders in Tandem at Moderate Reynolds Numbers

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Ali Vakil ◽  
Sheldon I. Green
Keyword(s):  
Numerical Study ◽  
Reynolds Numbers ◽  
Separation Distance ◽  
Monotonic Function ◽  
Circular Cylinders ◽  
Cylinder Surface ◽  
Two Dimensional ◽  
Tandem Cylinders ◽  
Laminar Wake ◽  
Cylinder Drag

Computer simulations of the flow around a pair of two-dimensional, tandem circular cylinders in a flow, for Reynolds numbers in the range 1–40, are described. Cylinder surface-to-surface separations in the range 0.1<s/D<400 (D = cylinder diameter) were considered. The computed wake of a single cylinder at these low to moderate Reynolds numbers was in surprisingly good agreement with the laminar wake approximation, and a simple theory is presented to explain this agreement. With tandem cylinders, the drag on the downstream cylinder is a monotonic function of the cylinder separation. The laminar wake approximation can be used to explain reasonably well the variation in drag. The drag on the upstream cylinder is also a monotonic function of separation distance provided that the Reynolds number is less than about 10. For Reynolds numbers between 10 and 40, the upstream cylinder drag first decreases as separation increases up to a few diameters and then increases monotonically with separation distance.

Three-Dimensional Laminar Wall Jet Flows

2009 ◽  
Author(s):  
Kofi K. Adane ◽  
Mark F. Tachie
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Jet Flows ◽  
Wall Jet ◽  
Navier Stokes Equation ◽  
Flow Geometry

The present article reports on both experimental and numerical study of three-dimensional laminar wall jet flows. The wall jet was created using a circular pipe of diameter 7 mm and flows into an open channel. The Reynolds numbers based on the pipe diameter and jet exit velocity were varied from 310 to 1300. A particle image velocimetry (PIV) was used to conduct detailed velocity measurements at various streamwise-transverse and streamwise-spanwise planes. A complete nonlinear incompressible Navier-Stokes equation was also solved using a co-located finite volume based in-house computational fluid dynamic (CFD) code. This code was used to compute the experimental flow geometry. From the PIV measurements and CFD results, velocities profiles and jet-half-widths were extracted at selected locations. It was observed that the numerical results are in reasonable agreement with the experimental data. The distributions of the velocities, jet-half-widths and visualisation of the secondary flows were used to provide insight into the characteristics of three-dimensional wall jet flows.

Two Dimensional Simulation of Flow and Heat Transfer Characteristics of Turbulent Jets

2010 ◽  
Author(s):  
Tarek Abdel-Salam
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbulent Jets ◽  
Reynolds Numbers ◽  
Impinging Jets ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Dimensional Simulation

In this study, flow and heat transfer characteristics of two-dimensional impinging jets are investigated numerically. Flow geometries under consideration are single and multiple impinging jets issued from a plane wall. Both confined and unconfined configurations are simulated. Effects of Reynolds number and the distance between the jets are investigated. Results are obtained with a finite volume CFD code. Structured grids are used in all cases of the present study. Turbulence is treated with a two equation k-ε model. Different jet velocities have been examined corresponding to Reynolds numbers of 5,000 to 20,000. Results show that the Reynolds number has significant effect on the heat transfer rate and has no effect on the location of the maximum Nusselt number.

scholarly journals Cherenkov Emission Generated by a Modulated Source in 2D Dispersive Photonic Crystal Slabs

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Erika Martínez-Sánchez ◽  
Gennadiy Burlak ◽  
Carlos Rodríguez-Garcia ◽  
Marisol Gallardo-Heredia ◽  
Ulises Avila-López
Keyword(s):  
Photonic Crystal ◽  
Numerical Analysis ◽  
Spatial Frequency ◽  
Optical Radiation ◽  
Numerical Study ◽  
Two Dimensional ◽  
Periodic Medium ◽  
Slab Surface ◽  
Photonic Crystal Slabs ◽  
Spatial Frequency Domain

This work presents a systematic numerical study of Cherenkov optical radiation generated by a modulated source that moves with uniform velocity on a two-dimensional (2D) photonic crystal (PCr) slab surface. We apply the FDTD technique with emphasis on the dispersion properties of the periodic medium to perform our numerical analysis. The field oscillations generated at the passage of a modulated source in the PCr produce a series of spectral resonances corresponding to the eigenmodes in the spatial frequency domain for the photonic slab. The amplitudes of the field oscillations have maximal values in the group cone closely to the path of the moving charge.

A Parametric Investigation of Jet and Vortex Actuator

2014 ◽  
Author(s):  
Sertac Cadirci ◽  
Hasan Gunes
Keyword(s):  
Numerical Study ◽  
Active Flow Control ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Wall Jet ◽  
Induced Flow ◽  
Zero Net Mass Flux ◽  
Active Flow ◽  
Jet Velocities ◽  
Plate Width

The Jet and Vortex Actuator (JaVA) is a zero-net-mass flux device for active flow control. In this numerical study, we present a parametric study of JaVA in quiescent water and obtain time-averaged flow and vorticity fields. We systematically investigate the effect of the governing parameters that affect on the JaVA - induced flow characteristics. Three jet Reynolds numbers are investigated in detail; ReJ = 68, 150 and 250 and for each jet-Reynolds number, four different wide-slot to plate width ratios are considered: gw = 0. 0166, 0.0338, 0.066 and 0.10. In all cases, the scaled amplitude is kept at Sa = 0.15 and 0.30 so that a total of 24 different simulations are investigated. JaVA - induced flow types are classified in five groups: wall-jet, vertical-oblique jet, chaotic jet, weak jet and vortex mode. Based on the governing parameters (Sa, ReJ and gw) all these flow types have been identified the jet-momentums are calculated from phase-averaged jet velocities obtained from numerical modeling results and compared to each other. It is found that generally the vortex mode transports the highest momentum flux followed by a chaotic jet.

scholarly journals Numerical study of the quenching of a laminar premixed hydrogen flame

2018 ◽  
Vol 240 ◽  
pp. 01031 ◽  
Author(s):  
Björn Pfeiffelmann ◽  
Ali Cemal Benim
Keyword(s):  
Steady State ◽  
Reaction Mechanism ◽  
Numerical Analysis ◽  
Numerical Study ◽  
Solid Wall ◽  
Two Dimensional ◽  
Detailed Mechanism ◽  
One Dimensional ◽  
Hydrogen Flame ◽  
Detailed Reaction Mechanism

A numerical analysis of the quenching of a laminar, premixed hydrogen-air flame is presented. A global and a detailed reaction mechanism are considered. First, one-dimensional flame propagation is analyzed and the models are validated based on the predicted flame speed. Subsequently, the quenching near a solid wall of a duct is analyzed, within a two-dimensional, steady-state formulation. Finally, propagation of a flame front through a quenching mesh, within an unsteady, two-dimensional analysis is considered. It is observed that the global mechanism does not predict a quenching of the flame by the mesh, whereas the detailed mechanism does.

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