LES and PANS of Turbulent Flow Through a Staggered Tube Bundle

2017 ◽  
Author(s):  
G. Minelli ◽  
S. Krajnović ◽  
B. Basara
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Tube Bundle ◽  
Dominant Frequency ◽  
Navier Stokes ◽  
Numerical Techniques ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Through ◽  
Good Agreement

Two unsteady numerical techniques, Partially-Averaged Navier Stokes (PANS) and Large Eddy Simulation (LES), are used to predict the flow in a tube bundle. The results were compared with the existing experimental data. Both methods predicted the flow in a relatively good agreement with the experimental data although the PANS simulation used only fifty percent of the computational nodes compared to the LES. The results of the simulations are used to study the unsteadiness in the flow and identify a dominant frequency of the flow.

Comparison of Partially Averaged Navier–Stokes and Large-Eddy Simulations of the Flow Around a Cuboid Influenced by Crosswind

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Siniša Krajnović ◽  
Per Ringqvist ◽  
Branislav Basara
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Large Eddy Simulations ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Better Than ◽  
Good Agreement ◽  
Near Wall

The paper presents a partially averaged Navier–Stokes (PANS) simulation of the flow around a cuboid influenced by crosswind. The results of the PANS prediction are validated against experimental data and results of a large-eddy simulation (LES) made using the same numerical conditions as PANS. The PANS shows good agreement with the experimental data. The prediction of PANS was found to be better than that of the LES in flow regions where simulations suffered from poor near-wall resolution.

scholarly journals ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher

2017 ◽  
Vol 14 (03) ◽  
pp. 1750021 ◽  
Author(s):  
A. Niktash ◽  
B. P. Huynh
Keyword(s):  
Natural Ventilation ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Interior Space ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method ◽  
Good Agreement

A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.

scholarly journals Jet Noise in Airframe Integration and Shielding

2020 ◽  
Vol 10 (2) ◽  
pp. 511
Author(s):  
Saman Salehian ◽  
Reda Mankbadi
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Jet Noise ◽  
Numerical Approach ◽  
Navier Stokes ◽  
Complex Geometries ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

This paper reviews and presents new results on the effect of airframe integration and shielding on jet noise. Available experimental data on integration effects are analyzed. The available options for the computation of jet noise are discussed, and a practical numerical approach for the present topic is recommended. Here, it is demonstrated how a hybrid large eddy simulation—unsteady Reynolds-averaged Navier-Stokes approach can be implemented to simulate the effect of shielding on radiated jet noise. This approach provides results consistent with the experiment and suggests a framework for studying more complex geometries involving airframe integration effects.

scholarly journals Large Eddy Simulation of Scalar Mixing in Jet in a Cross-Flow

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Asela Uyanwaththa ◽  
Weeratunge. Malalasekera ◽  
Graham Hargrave ◽  
Mark Dubal
Keyword(s):  
Experimental Data ◽  
Velocity Field ◽  
Large Eddy Simulation ◽  
Cross Flow ◽  
Passive Scalar ◽  
Scalar Mixing ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Fuel Mixing ◽  
Good Agreement

Jet in a cross-flow (JICF) is a flow arrangement found in many engineering applications, especially in gas turbine air–fuel mixing. Understanding of scalar mixing in JICF is important for low NOx burner design and operation, and numerical simulation techniques can be used to understand both spatial and temporal variation of air–fuel mixing quality in such applications. In this paper, mixing of the jet stream with the cross-flow is simulated by approximating the jet flow as a passive scalar and using the large eddy simulation (LES) technique to simulate the turbulent velocity field. A posteriori test is conducted to assess three dynamic subgrid scale models in modeling jet and cross-flow interaction with the boundary layer flow field. Simulated mean and Reynolds stress component values for velocity field and concentration fields are compared against experimental data to assess the capability of the LES technique, which showed good agreement between numerical and experimental results. Similarly, time mean and standard deviation values of passive scalar concentration also showed good agreement with experimental data. In addition, LES results are further used to discuss the scalar mixing field in the downstream mixing region.

scholarly journals Numerical Analysis of Flow Behavior in a Rectangular Channel with Submerged Weirs

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1396
Author(s):  
Oscar Herrera-Granados
Keyword(s):  
Flow Behavior ◽  
Rectangular Channel ◽  
Navier Stokes ◽  
Quadrant Analysis ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Rans Models ◽  
Flow Through ◽  
Proper Estimation ◽  
Good Agreement

In this contribution, different 3D numerical approaches are applied in order to simulate the behaviour of turbulent flow through a rectangular channel with broad-crested weirs. In addition, water flow velocities, using Acoustic Doppler Velocimetry (ADV) instrumentation, were recorded. Two turbulence quantities are estimated using the laboratory records and were compared with those computed with the Large Eddy Simulation (LES) and Reynolds Averaged Navier–Stokes (RANS) models. Additionally, a quadrant analysis of the laboratory records was carried out. The output of the models presents good agreement with the time-averaged parameters, but is not sufficient for the proper estimation of the turbulence quantities.

Assessment of the capabilities of FireFOAM to model large-scale fires in a well-confined and mechanically ventilated multi-compartment structure

2017 ◽  
Vol 36 (1) ◽  
pp. 3-29 ◽  
Author(s):  
Duy Le ◽  
Jeffrey Labahn ◽  
Tarek Beji ◽  
Cecile B Devaud ◽  
Elizabeth J Weckman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Large Scale ◽  
Detailed Comparison ◽  
Equation Model ◽  
Mechanically Ventilated ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Experimental Values ◽  
Good Agreement

This article presents a large eddy simulation study of a pool fire in a well-confined and mechanically ventilated multi-room configuration. The capabilities of FireFOAM are assessed by comparing the numerical results to a well-documented set of experimental data available from Propagation d’un Incendie pour des Scénarios Multi-locaux Elémentaires. The eddy dissipation concept, finite volume discrete ordinate method, and one k-equation model are used for combustion, thermal radiation, and sub-grid scale closure, respectively. The main boundary conditions are imposed based on the experimental profiles. A detailed comparison is made with available experimental data. Good agreement between the large eddy simulation results and experimental values is achieved for temperatures, velocity, CO2 volume concentrations, and pressures for most compartments. There are some noticeable underpredictions of temperature in the outlet room. Overall, FireFOAM is shown to have good predictive capabilities for the present confined large-scale fire scenario.

scholarly journals Large Eddy Simulation of a flow through circular tube bundle

2011 ◽  
Vol 35 (9) ◽  
pp. 4393-4406 ◽  
Author(s):  
M. Salinas-Vázquez ◽  
M.A. de la Lama ◽  
W. Vicente ◽  
E. Martínez
Keyword(s):  
Large Eddy Simulation ◽  
Circular Tube ◽  
Tube Bundle ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Through

On LES Methods Applied to Seal Geometries

2012 ◽  
Author(s):  
James Tyacke ◽  
Richard Jefferson-Loveday ◽  
Paul Tucker
Keyword(s):  
Maximum Error ◽  
Labyrinth Seal ◽  
Navier Stokes ◽  
Final Solution ◽  
Complex Flow ◽  
Eddy Simulation ◽  
Wide Range ◽  
Large Eddy ◽  
Rans Models ◽  
Flow Through

Nine Large Eddy Simulation (LES) methods are used to simulate flow through two labyrinth seal geometries and are compared with a wide range of Reynolds-Averaged Navier-Stokes (RANS) solutions. These involve one-equation, two-equation and Reynolds Stress RANS models. Also applied are linear and nonlinear pure LES models, hybrid RANS-Numerical-LES (RANS-NLES) and Numerical-LES (NLES). RANS is found to have a maximum error and a scatter of 20%. A similar level of scatter is also found among the same turbulence model implemented in different codes. In a design context, this makes RANS unusable as a final solution. Results show that LES and RANS-NLES is capable of accurately predicting flow behaviour of two seals with a scatter of less than 5%. The complex flow physics gives rise to both laminar and turbulent zones making most LES models inappropriate. Nonetheless, this is found to have minimal tangible results impact. In accord with experimental observations, the ability of LES to find multiple solutions due to solution non-uniqueness is also observed.

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