Large Eddy Simulation of Hydraulic Characteristics after New Lateral Aerator

2011 ◽  
Vol 255-260 ◽  
pp. 3466-3471
Author(s):  
Guo Jing Li ◽  
Guang Qing Dai ◽  
Qing Yang ◽  
Xu Dong Ma
Keyword(s):  
Flow Condition ◽  
Lateral Wall ◽  
Vof Method ◽  
Numerical Results ◽  
Maximum Pressure ◽  
Hydraulic Characteristics ◽  
Eddy Simulation ◽  
Bottom Cavity ◽  
Large Eddy ◽  
Lateral Cavity

The simulation of hydraulic characteristics was carried out with Larger Eddy Simulation (LES) and Volume of Fluid (VOF) method. The numerical results show that the flow condition is smooth, the length of lateral cavity gradually increases with the size of lateral enlargement increases, the maximum pressure value on the lateral wall appears after the bottom cavity, the upper part of the lateral cavity region was longer than the lower part due to gravity and the backwater does not intrude into bottom cavity. The numerical results agree well with the experimental date. The new lateral aerator has good hydraulic characteristics and the LES with VOF method can well predict the hydraulic characteristics after the new lateral aerator.

Larger-Eddy Simulation of Velocity Fluctuation in a Mixing T-Junction

2012 ◽  
Vol 152-154 ◽  
pp. 1313-1318
Author(s):  
Tao Lu ◽  
Su Mei Liu ◽  
Ping Wang ◽  
Wei Yyu Zhu
Keyword(s):  
Experimental Data ◽  
Velocity Fluctuation ◽  
Flow Model ◽  
Numerical Results ◽  
Mean Square ◽  
Main Duct ◽  
Velocity Fluctuations ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Les Model

Velocity fluctuations in a mixing T-junction were simulated in FLUENT using large-eddy simulation (LES) turbulent flow model with sub-grid scale (SGS) Smagorinsky–Lilly (SL) model. The normalized mean and root mean square velocities are used to describe the time-averaged velocities and the velocities fluctuation intensities. Comparison of the numerical results with experimental data shows that the LES model is valid for predicting the flow of mixing in a T-junction junction. The numerical results reveal the velocity distributions and fluctuations are basically symmetrical and the fluctuation at the upstream of the downstream of the main duct is stronger than that at the downstream of the downstream of the main duct.

Very Large Eddy Simulation of Passive Drag Control for a D-Shaped Cylinder

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Xingsi Han ◽  
Siniša Krajnović
Keyword(s):  
Large Eddy Simulation ◽  
Flow Control ◽  
Control Problem ◽  
Bluff Body ◽  
Numerical Study ◽  
Numerical Results ◽  
Complex Flow ◽  
Local Disturbance ◽  
Eddy Simulation ◽  
Large Eddy

The numerical study reported here deals with the passive flow control around a two-dimensional D-shaped bluff body at a Reynolds number of Re=3.6×104. A small circular control cylinder located in the near wake behind the main bluff body is employed as a local disturbance of the shear layer and the wake. 3D simulations are carried out using a newly developed very large eddy simulation (VLES) method, based on the standard k − ε turbulence model. The aim of this study is to validate the performance of this method for the complex flow control problem. Numerical results are compared with available experimental data, including global flow parameters and velocity profiles. Good agreements are observed. Numerical results suggest that the bubble recirculation length is increased by about 36% by the local disturbance of the small cylinder, which compares well to the experimental observations in which the length is increased by about 38%. A drag reduction of about 18% is observed in the VLES simulation, which is quite close to the experimental value of 17.5%. It is found that the VLES method is able to predict the flow control problem quite well.

scholarly journals Prediction of a Small-Scale Pool Fire with FireFoam

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Camilo Andrés Sedano ◽  
Omar Darío López ◽  
Alexander Ladino ◽  
Felipe Muñoz
Keyword(s):  
Numerical Results ◽  
Pool Fire ◽  
Flame Height ◽  
Combustion Model ◽  
Small Scale ◽  
Average Temperature ◽  
Eddy Simulation ◽  
Fire Experiment ◽  
Large Eddy ◽  
Good Agreement

A computational model using Large Eddy Simulation (LES) for turbulence modelling was implemented, by means of the Eddy Dissipation Concept (EDC) combustion model using the fireFoam solver. A small methanol pool fire experiment was simulated in order to validate and compare the numerical results, hence trying to validate the effectiveness of the solver. A detailed convergence analysis is performed showing that a mesh of approximately two million elements is sufficient to achieve satisfactory numerical results (including chemical kinetics). A good agreement was achieved with some of the experimental and previous computational results, especially in the prediction of the flame height and the average temperature contours.

scholarly journals Prediction of a methane circular pool fire with fireFoam

2018 ◽  
Vol 240 ◽  
pp. 05026
Author(s):  
Camilo Sedano ◽  
Omar López ◽  
Alexander Ladino ◽  
Felipe Muñoz
Keyword(s):  
Large Eddy Simulation ◽  
Convergence Analysis ◽  
Three Dimensional ◽  
Numerical Results ◽  
Pool Fire ◽  
Medium Scale ◽  
Eddy Simulation ◽  
Large Eddy

In the present work, the fireFoam solver was used with Large Eddy Simulation (LES) and the Eddy Dissipation Concept (EDC) for modelling a medium-scale methane pool fire. A convergence analysis performed, showed that a 2 Million elements three-dimensional mesh, is good enough to attain good numerical results. By comparing the numerical results obtained, with the experimental ones, as well as numerical results from previous studies, it was proven that the fireFoam solver is able to obtain satisfactory results.

Large Eddy Simulation of Hydraulic Characteristics of Flow around Two Parallel Circular Cylinders

2012 ◽  
Vol 468-471 ◽  
pp. 1862-1865
Author(s):  
X.J. Zhao ◽  
W.L. Wei ◽  
Xi Wang ◽  
Ming Qin Liu
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Circular Cylinders ◽  
Hydraulic Characteristics ◽  
Step Method ◽  
Fractional Step Method ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Engineering Problems ◽  
Total Velocity

large eddy simulation cooperated with a physical fractional-step method was applied to simulate steady flow around two parallel circular cylinders. The total velocity vectors, pressure contours and vorticity magnitude are obtained. The modeling results conform to physical law, and show that the large eddy simulation theory has powerful capacity in simulation of microstructures of turbulent flows, and can be widely applied to the solution of real engineering problems.

Large-Eddy Simulation for Temperature Fluctuation of Mixing Hot and Cold Fluids in a Tee Junction

2010 ◽  
Author(s):  
T. Lu ◽  
W. Y. Zhu ◽  
K. S. Wang
Keyword(s):  
Large Eddy Simulation ◽  
Temperature Fluctuation ◽  
Flow Simulation ◽  
Temperature Fluctuations ◽  
Numerical Results ◽  
Piping System ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Tee Junction ◽  
Fluctuating Temperatures

In the present work the temperature fluctuations in a mixing tee were simulated on FLUENT platform using the Large-eddy simulation (LES) turbulent flow model with the sub-grid scale (SGS) model of Smagorinsky-Lilly (SL). The temperature and velocity fields, the normalized mean and fluctuating temperatures and velocities were predicted and analyzed with consideration of buoyancy. The normalized mean and fluctuating temperatures were defined to describe the time-averaged temperature and the time-averaged temperature fluctuation intensity. The numerical results of the normalized mean and fluctuating temperatures were compared with those of the experimental ones published in previous literature, which shows that numerical results have good agreement with the experimental data. The temperature fluctuations and power spectrum densities (PSD) at the locations having the strongest temperature fluctuations both in tee junction and on the walls were analyzed to evaluate the potential of thermal fatigue. The LES flow simulation and power spectral analysis are helpful for the Integrity evaluation of the structures such as the tee junction, elbow, piping system to predict the temperature fluctuation and thermal stripping in a tee junction of mixing hot and cold fluids.

scholarly journals Effects of Geometry and Hydraulic Characteristics of Shallow Reservoirs on Sediment Entrapment

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1725 ◽  
Author(s):  
Hamidreza Zahabi ◽  
Mohammadamin Torabi ◽  
Ebrahim Alamatian ◽  
Mehdi Bahiraei ◽  
Marjan Goodarzi
Keyword(s):  
Numerical Modeling ◽  
Software Package ◽  
Reasonable Agreement ◽  
Numerical Data ◽  
Considerable Effect ◽  
Hydraulic Characteristics ◽  
Eddy Simulation ◽  
Large Eddy ◽  
3D Software ◽  
Shallow Reservoirs

Sediment and deposition are among the main problems in dam engineering and other related fields. Because of the numerous advantages of numerical modeling, effects of different geometries of reservoirs on the flow pattern and deposition of sediments are investigated using the finite volume based Flow-3D software package. In this study, three rectangular reservoirs with different dimensional ratios are simulated using the large eddy simulation (LES) turbulence model. To validate the numerical modeling, existing experimental data is used. Results indicate that Flow-3D can accurately simulate flow and sediment deposition in the reservoirs, and the numerical data are in reasonable agreement with the experimental results. Numerical efforts showed that the amount of deposition in reservoirs is significantly dependent on the geometry. Among the modeled reservoirs, the 6 × 4 m one has the best performance. Moreover, it can be said that changing the position of the flow’s inlet and outlet of the reservoir does not have a considerable effect on increasing its efficiency.

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