scholarly journals Direct numerical simulations of two-phase laminar jet flows with different cross-section injection geometries

2002 ◽  
Vol 14 (10) ◽  
pp. 3655-3674 ◽  
Author(s):  
H. Abdel-Hameed ◽  
J. Bellan
Keyword(s):  
Numerical Simulations ◽  
Cross Section ◽  
Direct Numerical Simulations ◽  
Jet Flows ◽  
Two Phase ◽  
Laminar Jet

Modeling Wall Film Formation and Breakup Using an Integrated Interface-Tracking/Discrete-Phase Approach

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
M. Arienti ◽  
L. Wang ◽  
M. Corn ◽  
X. Li ◽  
M. C. Soteriou ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Level Set ◽  
Film Formation ◽  
Rectangular Channel ◽  
Grid Method ◽  
Direct Numerical Simulations ◽  
Liquid Jet ◽  
Two Phase ◽  
Local Flow ◽  
Air Jet

We propose a computationally tractable model for film formation and breakup based on data from experiments and direct numerical simulations. This work is a natural continuation of previous studies where primary atomization was modeled based on local flow information from a relatively low-resolution tracking of the liquid interface [Arienti and Soteriou, 2007, “Dynamics of Pulsed Jet in Crossflow,” ASME Paper No. GT2007-27816]. The submodels for film formation proposed here are supported by direct numerical simulations obtained with the refined level set grid method [Herrmann, 2008, “A Balanced Force Refined Level Set Grid Method for Two-Phase Flows on Unstructured Flow Solver Grids,” J. Comput. Phys., 227, pp. 2674–2706]. The overall approach is validated by a carefully designed experiment [Shedd et. al., 2009, “Liquid Jet Breakup by an Impinging Air Jet,” Forty-Seventh AIAA Aerospace Sciences Meeting. Paper No. AIAA-2009-0998], where the liquid jet is crossflow-atomized in a rectangular channel so that a film forms on the wall opposite to the injection orifice. The film eventually breaks up at the downstream exit of the channel. Comparisons with phase Doppler particle analyzer data and with nonintrusive film thickness point measurements complete this study.

scholarly journals Experiments and modelling of premixed laminar stagnation flame hydrodynamics

2011 ◽  
Vol 681 ◽  
pp. 340-369 ◽  
Author(s):  
JEFFREY M. BERGTHORSON ◽  
SEAN D. SALUSBURY ◽  
PAUL E. DIMOTAKIS
Keyword(s):  
Pressure Drop ◽  
Boundary Conditions ◽  
Strain Rate ◽  
Numerical Simulations ◽  
Laminar Flame ◽  
Flame Speed ◽  
Combustion Model ◽  
Jet Flows ◽  
Laminar Jet ◽  
Premixed Laminar

The hydrodynamics of a reacting impinging laminar jet, or stagnation flame, is studied experimentally and modelled using large activation energy asymptotic models and numerical simulations. The jet-wall geometry yields a stable, steady flame and allows for precise measurement and specification of all boundary conditions on the flow. Laser diagnostic techniques are used to measure velocity and CH radical profiles. The axial velocity profile through a premixed stagnation flame is found to be independent of the nozzle-to-wall separation distance at a fixed nozzle pressure drop, in accord with results for non-reacting impinging laminar jet flows, and thus the strain rate in these flames is only a function of the pressure drop across the nozzle. The relative agreement between the numerical simulations and experiment using a particular combustion chemistry model is found to be insensitive to both the strain rate imposed on the flame and the relative amounts of oxygen and nitrogen in the premixed gas, when the velocity boundary conditions on the simulations are applied in a manner consistent with the formulation of the streamfunction hydrodynamic model. The analytical model predicts unburned, or reference, flame speeds that are slightly lower than the detailed numerical simulations in all cases and the observed dependence of this reference flame speed on strain rate is stronger than that predicted by the model. Experiment and simulation are in excellent agreement for near-stoichiometric methane–air flames, but deviations are observed for ethylene flames with several of the combustion models used. The discrepancies between simulation and experimental profiles are quantified in terms of differences between measured and predicted reference flame speeds, or position of the CH-profile maxima, which are shown to be directly correlated. The direct comparison of the measured and simulated reference flame speeds, ΔSu, can be used to infer the difference between the predicted flame speed of the combustion model employed and the true laminar flame speed of the mixture, ΔSOf, i.e. ΔSu=ΔSOf, consistent with recently proposed nonlinear extrapolation techniques.

scholarly journals Direct numerical simulations of two-phase immiscible wakes

2014 ◽  
Vol 46 (4) ◽  
pp. 041409 ◽  
Author(s):  
Luca Biancofiore ◽  
François Gallaire ◽  
Patrice Laure ◽  
Elie Hachem
Keyword(s):  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Two Phase

scholarly journals Direct Numerical Simulations on Jets during the Propagation and Break down of Internal Solitary Waves on a Slope

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 671
Author(s):  
Jin Xu ◽  
Eldad J. Avital ◽  
Lingling Wang
Keyword(s):  
Numerical Simulations ◽  
Solitary Waves ◽  
Water Environment ◽  
Direct Numerical Simulations ◽  
Internal Solitary Waves ◽  
Jet Flows ◽  
Strong Mixing ◽  
Internal Interface ◽  
Transport Length ◽  
Moving Interface

Jet flows often have an important role in the water environment. The aim of this research is to study the dilution of jets due to complex velocity fields induced by internal solitary waves in stratified water. Direct numerical simulations are used to study vertical jet flows during the propagation and breaking of internal solitary waves (ISWs) with elevation type on a slope. Energy analysis shows that the internal interface is able to absorb kinetic energy from the jet and that for Re < 10,000 with Ri > 3.7, the ISWs can stay stable during the propagation within the presence of jet flows. The vortices jointly induced by the jets and the ISWs are observed at the bottom behind the ISW’s crest. The transport of the jet’s emitted scalar by the ISWs can be divided into two parts; some is transported by the moving interface and the rest by the bottom vortices. The ultimate transport length scales of two types are defined, and it is found that when the center of the jet inlet approaches the slope, the extension of the bottom vortices into the slope will lead to strong mixing. That causes increasing scalar concentration over the slope of the scalar that originated from the jet.

Detached direct numerical simulations of turbulent two-phase bubbly channel flow

2011 ◽  
Vol 37 (6) ◽  
pp. 647-659 ◽  
Author(s):  
Igor A. Bolotnov ◽  
Kenneth E. Jansen ◽  
Donald A. Drew ◽  
Assad A. Oberai ◽  
Richard T. Lahey ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Channel Flow ◽  
Direct Numerical Simulations ◽  
Two Phase

Direct numerical simulations of autoignition in turbulent two-phase flows

2009 ◽  
Vol 32 (2) ◽  
pp. 2275-2282 ◽  
Author(s):  
P. Schroll ◽  
A.P. Wandel ◽  
R.S. Cant ◽  
E. Mastorakos
Keyword(s):  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Two Phase Flows ◽  
Two Phase

scholarly journals Влияние числа Рейнольдса на распределение пульсационной составляющей вихря скорости по сечению плоского канала

2019 ◽  
Vol 89 (3) ◽  
pp. 347
Author(s):  
Ю.Г. Чесноков
Keyword(s):  
Reynolds Number ◽  
Numerical Simulations ◽  
Cross Section ◽  
Liquid Flow ◽  
Direct Numerical Simulations ◽  
Mean Square ◽  
Flat Channel ◽  
Analysis Of Results ◽  
The Cross ◽  
Vortex Velocity

AbstractBased on the analysis of results from different authors using direct numerical simulations of the liquid flow in a flat channel, the effect of Reynolds number on the distribution of mean-square values of projections of a pulsed component of vortex velocity through the cross-section of a flat channel has been studied.

Towards direct numerical simulations of low-Mach number turbulent reacting and two-phase flows using immersed boundaries

2016 ◽  
Vol 131 ◽  
pp. 123-141 ◽  
Author(s):  
Abouelmagd Abdelsamie ◽  
Gordon Fru ◽  
Timo Oster ◽  
Felix Dietzsch ◽  
Gábor Janiga ◽  
...  
Keyword(s):  
Mach Number ◽  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Two Phase Flows ◽  
Two Phase ◽  
Low Mach Number ◽  
Immersed Boundaries
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