Direct numerical simulation of transitional and turbulent buoyant planar jet flames

2004 ◽  
Vol 16 (12) ◽  
pp. 4443-4461 ◽  
Author(s):  
K. Mehravaran ◽  
F. A. Jaberi
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Jet Flames ◽  
Planar Jet

VISUALIZATION OF TURBULENT REACTIVE JET BY USING DIRECT NUMERICAL SIMULATION

2013 ◽  
Vol 04 (supp01) ◽  
pp. 1341001 ◽  
Author(s):  
TOMOAKI WATANABE ◽  
YASUHIKO SAKAI ◽  
KOUJI NAGATA ◽  
OSAMU TERASHIMA ◽  
HIROKI SUZUKI ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Reaction Rate ◽  
Jet Flow ◽  
Ambient Flow ◽  
Planar Jet ◽  
Order Chemical Reaction ◽  
Fast Chemical

Direct numerical simulation (DNS) of turbulent planar jet with a second-order chemical reaction (A + B → R) is performed to investigate the processes of mixing and chemical reactions in spatially developing turbulent free shear flows. Reactant A is premixed into the jet flow, and reactant B is premixed into the ambient flow. DNS is performed at three different Damköhler numbers (Da = 0.1,1, and 10). Damköhler number is a ratio of a time scale of a flow to that of chemical reactions, and in this study, the large Da means a fast chemical reaction, and the small Da means a slow chemical reaction. The visualization of velocity field shows that the jet flow is developed by entraining the ambient fluid. The visualization of concentration of reactant A shows that concentration of reactant A for Da = 1 and 10 becomes very small in the downstream region because the chemical reaction consumes the reactants and reactant A is diffused with the jet development. By comparison of the profiles of chemical reaction rate and concentration of product R, it is found that product R for Da = 10 is produced by the chemical reaction at the interface between the jet and the ambient fluids and is diffused into the jet flow, whereas product R for Da = 0.1 is produced in the jet flow after reactants A and B are well mixed.

Instability waves in a low-Reynolds-number planar jet investigated with hybrid simulation combining particle tracking velocimetry and direct numerical simulation

2010 ◽  
Vol 655 ◽  
pp. 344-379 ◽  
Author(s):  
TAKAO SUZUKI ◽  
HUI JI ◽  
FUJIO YAMAMOTO
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Hybrid Simulation ◽  
Velocity Fields ◽  
Computational Time ◽  
Spatial Problem ◽  
Instability Waves ◽  
Planar Jet

Instability waves in a laminar planar jet are extracted using hybrid unsteady-flow simulation combining particle tracking velocimetry (PTV) and direct numerical simulation (DNS). Unsteady velocity fields on a laser sheet in a water tunnel are measured with time-resolved PTV; subsequently, PTV velocity fields are rectified in a least squares sense so that the equation of continuity is satisfied, and they are transplanted to a two-dimensional incompressible Navier–Stokes solver by setting a multiple of the computational time step equal to the frame rate of the PTV system. As a result, the unsteady hybrid velocity field approaches that of the measured one over time, and we can simultaneously acquire the unsteady pressure field. The resultant set of flow quantities satisfies the governing equations, and their resolution is comparable to that of numerical simulation with the noise level much lower than the original PTV data. From hybrid unsteady velocity fields, we extract eigenfunctions using bi-orthogonal decomposition as a spatial problem for viscous instability. We also investigate stability/convergence characteristics of the hybrid simulation referring to linear stability analysis.

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