Large-Eddy Simulation of Supercritical-Pressure Round Jets

AIAA Journal ◽  
2010 ◽  
Vol 48 (9) ◽  
pp. 2133-2144 ◽  
Author(s):  
Thomas Schmitt ◽  
Laurent Selle ◽  
Anthony Ruiz ◽  
Bénédicte Cuenot
Keyword(s):  
Large Eddy Simulation ◽  
Supercritical Pressure ◽  
Round Jets ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Large eddy simulation of two parallel round jets

2019 ◽  
Vol 1359 ◽  
pp. 012020
Author(s):  
A V Barsukov ◽  
M V Philippov ◽  
I A Chokhar ◽  
V V Terekhov
Keyword(s):  
Large Eddy Simulation ◽  
Round Jets ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Subgrid-scale models and large-eddy simulation of oxygen stream disintegration and mixing with a hydrogen or helium stream at supercritical pressure

2011 ◽  
Vol 679 ◽  
pp. 156-193 ◽  
Author(s):  
EZGI S. TAŞKINOĞLU ◽  
JOSETTE BELLAN
Keyword(s):  
Heat Flux ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Correction Term ◽  
A Priori ◽  
Supercritical Pressure ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Impact

For flows at supercritical pressure, p, the large-eddy simulation (LES) equations consist of the differential conservation equations coupled with a real-gas equation of state, and the equations utilize transport properties depending on the thermodynamic variables. Compared to previous LES models, the differential equations contain not only the subgrid-scale (SGS) fluxes but also new SGS terms, each denoted as a ‘correction’. These additional terms, typically assumed null for atmospheric pressure flows, stem from filtering the differential governing equations and represent differences, other than contributed by the convection terms, between a filtered term and the same term computed as a function of the filtered flow field. In particular, the energy equation contains a heat-flux correction (q-correction) which is the difference between the filtered divergence of the molecular heat flux and the divergence of the molecular heat flux computed as a function of the filtered flow field. We revisit here a previous a priori study where we only had partial success in modelling the q-correction term and show that success can be achieved using a different modelling approach. This a priori analysis, based on a temporal mixing-layer direct numerical simulation database, shows that the focus in modelling the q-correction should be on reconstructing the primitive variable gradients rather than their coefficients, and proposes the approximate deconvolution model (ADM) as an effective means of flow field reconstruction for LES molecular heat-flux calculation. Furthermore, an a posteriori study is conducted for temporal mixing layers initially containing oxygen (O) in the lower stream and hydrogen (H) or helium (He) in the upper stream to examine the benefit of the new model. Results show that for any LES including SGS-flux models (constant-coefficient gradient or scale-similarity models; dynamic-coefficient Smagorinsky/Yoshizawa or mixed Smagorinsky/Yoshizawa/gradient models), the inclusion of the q-correction in LES leads to the theoretical maximum reduction of the SGS molecular heat-flux difference; the remaining error in modelling this new subgrid term is thus irreducible. The impact of the q-correction model first on the molecular heat flux and then on the mean, fluctuations, second-order correlations and spatial distribution of dependent variables is also demonstrated. Discussions on the utilization of the models in general LES are presented.

Large Eddy Simulation of Multiple Round Impinging Jets

2011 ◽  
Author(s):  
N. Kharoua ◽  
L. Khezzar ◽  
Z. Nemouchi
Keyword(s):  
Large Eddy Simulation ◽  
Flow Behavior ◽  
Impinging Jets ◽  
Heated Plate ◽  
Round Jets ◽  
Eddy Simulation ◽  
Line Array ◽  
Large Eddy ◽  
Multiple Round ◽  
Experimental Findings

Large eddy simulation of flow and heat transfer of multiple turbulent round jets in an in-line array impinging on a flat plate is conducted. The full geometry is used in the simulation of the 9 jets. To capture the interactions between the jets the full geometry is meshed in this work. The Reynolds number based on the nozzle diameter of 13 mm, jet initial average velocity of 23.88 m/s and properties of air at room temperature was equal to 20,000. The computations of the mean vertical and horizontal component of the velocity vector in selected planes show very good agreement with experiments. The flow behavior of the jets agrees with experimental findings in terms of vortices surrounding the jets and the appearance of the asymmetry on and close to the flat impingement plane. The predicted mean surface Nusselt number on the flat heated plate shows also excellent agreement with experiments and a relative maximum between the jets in the region of the upwash fountain flow where the wall jets collide, not seen in the experiments, is captured by the numerics.

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