Numerical Simulation and Experimental Verification of Butterfly Porous Fences

2012 ◽  
Vol 501 ◽  
pp. 413-417
Author(s):  
Zhen Ya Duan ◽  
Ying Ying Dong ◽  
Fu Lin Zheng ◽  
Jun Mei Zhang
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Flow Characteristics ◽  
Research Progress ◽  
Comparison Results ◽  
Optimum Porosity ◽  
Shelter Effect ◽  
Sheltering Effect ◽  
Wind Reduction ◽  
Porous Fence

In this paper, the domestic and foreign research progress of numerical simulation on the porous fence is introduced briefly, and a numerical model is established to simulate the flow characteristics behind the butterfly porous fence through the FLUENT software. The comparison results found good agreement between the numerical model and wind tunnel experimental data with an error of 7.8% in the wind reduction ratio, indicating the present numerical model can be used to undertake study on butterfly and non-planar porous fences. The effect of porosity on the flow characteristics behind the butterfly porous fence have been evaluated using the present model to determine an optimum porosity for sheltering effect of an isolated porous fence. As a result, the butterfly porous fences with a range of porosity from 0.27 to 0.32 seem to have a better shelter effect among the studied porosities, and all the wind reduction ratios approach to 60%.

Effect of a Bottom Gap on the Flow Characteristics behind Non-Planar Porous Fence

2011 ◽  
Vol 356-360 ◽  
pp. 1391-1395 ◽  
Author(s):  
Zhen Ya Duan ◽  
Wen Xiang Yang ◽  
Tian Shun Wang ◽  
Jun Mei Zhang
Keyword(s):  
Turbulence Intensity ◽  
Flow Characteristics ◽  
Stream Velocity ◽  
Large Area ◽  
Mean Velocity ◽  
Gap Ratio ◽  
Shelter Effect ◽  
Wind Reduction ◽  
Porous Fence ◽  
Velocity Field Measurement

The flow field behind non-planar porous fence of geometric porosity ε=0.273 with various bottom gaps (G) has been investigated by hot-wire anemometer velocity field measurement technique in a wind tunnel experiment. Seven gap ratios G/H=0.000, 0.025, 0.075, 0.125, 0.150, 0.175, 0.200 of non-planar porous fence were tested in this study with the free-stream velocity fixed at 10m/s. The experimental data were analyzed and the turbulence intensity and wind reduction ratios for different gaps of the porous fence were calculated to estimate the shelter effect of a non-planar porous fence model. The results show that the gap ratio G/H=0.150 gives the best shelter effect among the seven gaps of the non-planar porous fence tested in this study, having a better mean velocity and turbulence intensity as well as wind reduction ratio in a large area behind the non-planar porous fence.

scholarly journals Research Progress on Numerical Simulation of Two-phase Flow in the Gas-solid Fluidized Bed

2021 ◽  
Vol 259 ◽  
pp. 04002
Author(s):  
Shujie Sun ◽  
Xiaosai Dong ◽  
Jie Wang ◽  
Haodong Zhang ◽  
Zhenya Duan
Keyword(s):  
Numerical Simulation ◽  
Fluidized Bed ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Research Progress ◽  
Phase Flow ◽  
Two Phase ◽  
Drag Model ◽  
Reaction Characteristics ◽  
Coupling Algorithm

It is difficult to accurately measure the parameters of solid particles in the experiment of the gas-solid fluidized bed. The numerical simulation plays an important role to accurately describe flow characteristics in the fluidized bed. Combined with the research work of the research group, this paper analyzes the application of numerical simulation of fluidized bed from the aspects of gas-solid coupling algorithm, drag model, flow characteristics, and reaction characteristics based on the previous studies. The specificity improvement of the gas-solid coupling algorithm and the regional application of the drag model is the trend of the recent development of numerical simulation. Previous studies mainly focus on the gas-solid two-phase flow field characteristics in the traditional fluidized bed, but few on the complex flow characteristics such as gas-solid reverse flow and the coupling with reaction characteristics. It is of great significance for designing a novel fluidized bed reactor to realize gas-solid continuous reaction to establish and improve the numerical simulation method of gas-solid non-catalytic reaction.

scholarly journals The fence experiment – full-scale lidar-based shelter observations

2016 ◽  
Vol 1 (2) ◽  
pp. 101-114 ◽  
Author(s):  
Alfredo Peña ◽  
Andreas Bechmann ◽  
Davide Conti ◽  
Nikolas Angelou
Keyword(s):  
Sonic Anemometer ◽  
Vertical Plane ◽  
Stable Case ◽  
Sonic Anemometers ◽  
Shelter Effect ◽  
Sheltering Effect ◽  
Inflow Conditions ◽  
Far Wake ◽  
Relative Wind ◽  
Porous Fence

Abstract. We present shelter measurements of a fence from a field experiment in Denmark. The measurements were performed with three lidars scanning on a vertical plane downwind of the fence. Inflow conditions are based on sonic anemometer observations of a nearby mast. For fence-undisturbed conditions, the lidars' measurements agree well with those from the sonic anemometers and, at the mast position, the average inflow conditions are well described by the logarithmic profile. Seven cases are defined based on the relative wind direction to the fence, the fence porosity, and the inflow conditions. The larger the relative direction, the lower the effect of the shelter. For the case with the largest relative directions, no sheltering effect is observed in the far wake (distances ⪆ 6 fence heights downwind of the fence). When comparing a near-neutral to a stable case, a stronger shelter effect is noticed. The shelter is highest below  ≈ 1.46 fence heights and can sometimes be observed at all downwind positions (up to 11 fence heights downwind). Below the fence height, the porous fence has a lower impact on the flow close to the fence compared to the solid fence. Velocity profiles in the far wake converge onto each other using the self-preserving forms from two-dimensional wake analysis.

Study on the Flow Characteristics of Rope and Cylinder With Large-Eddy Simulation

2018 ◽  
Author(s):  
Hui Cheng ◽  
Liuyi Huang ◽  
Yi Ni ◽  
Fenfang Zhao ◽  
Xinxin Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Large Eddy Simulation ◽  
Flow Characteristics ◽  
Numerical Results ◽  
Hydrodynamic Characteristics ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Smooth Cylinder ◽  
Force Calculation

Three-strand rope is the dominant material in fishing net and fish cage. Smooth cylinder is a common numerical model of net twines in the drag force calculation. This paper studied the hydrodynamic characteristics of ropes and smooth cylinders. Large Eddy Simulation was applied to the numerical simulation. Numerical results indicated that the drag coefficient of rope was much smaller than that of smooth cylinder when Re = 3900. The detailed analysis and comparison of their flow characteristics explained the reason. The specific of eddy shedding and wake pattern were presented in the numerical results.

Broadband liner impedance eduction for multimodal acoustic propagation in the presence of a mean flow

2016 ◽  
Vol 11 (2) ◽  
pp. 150-155
Author(s):  
R. Troian ◽  
D. Dragna ◽  
C. Bailly ◽  
M.-A. Galland
Keyword(s):  
Numerical Model ◽  
Flow Characteristics ◽  
Acoustic Propagation ◽  
Rational Fraction ◽  
Physical Parameters ◽  
Mean Flow ◽  
Linearized Euler Equations ◽  
Grazing Flow ◽  
Propagation Medium ◽  
Difference Time

Modeling of acoustic propagation in a duct with absorbing treatment is considered. The surface impedance of the treatment is sought in the form of a rational fraction. The numerical model is based on a resolution of the linearized Euler equations by finite difference time domain for the calculation of the acoustic propagation under a grazing flow. Sensitivity analysis of the considered numerical model is performed. The uncertainty of the physical parameters is taken into account to determine the most influential input parameters. The robustness of the solution vis-a-vis changes of the flow characteristics and the propagation medium is studied.

scholarly journals Blowing and drifting snow in Alpine terrain: numerical simulation and related field measurements

1998 ◽  
Vol 26 ◽  
pp. 174-178 ◽  
Author(s):  
Peter Gauer
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Three Dimensional ◽  
Field Measurements ◽  
Blowing Snow ◽  
Related Field ◽  
Drifting Snow ◽  
Physically Based ◽  
Snow Transport

A physically based numerical model of drifting and blowing snow in three-dimensional terrain is developed. The model includes snow transport by saltation and suspension. As an example, a numerical simulation for an Alpine ridge is presented and compared with field measurements.

scholarly journals Wind shear over the Nice Côte d'Azur airport: case studies

2013 ◽  
Vol 13 (9) ◽  
pp. 2223-2238 ◽  
Author(s):  
A. Boilley ◽  
J.-F. Mahfouf
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Wind Shear ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Measurement Campaign ◽  
Wind Lidar ◽  
Real Time Applications ◽  
Wind Shears

Abstract. The Nice Côte d'Azur international airport is subject to horizontal low-level wind shears. Detecting and predicting these hazards is a major concern for aircraft security. A measurement campaign took place over the Nice airport in 2009 including 4 anemometers, 1 wind lidar and 1 wind profiler. Two wind shear events were observed during this measurement campaign. Numerical simulations were carried out with Meso-NH in a configuration compatible with near-real time applications to determine the ability of the numerical model to predict these events and to study the meteorological situations generating an horizontal wind shear. A comparison between numerical simulation and the observation dataset is conducted in this paper.

Numerical Simulation for Microconvection Around Nano-Particle With Brownian Motion in Liquid

2003 ◽  
Author(s):  
B. X. Wang ◽  
H. Li ◽  
X. F. Peng ◽  
L. X. Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Brownian Motion ◽  
Numerical Model ◽  
Temperature Gradient ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Nano Particles ◽  
Analytic Method ◽  
Nano Particle

The development of a numerical model for analyzing the effect of the nano-particles’ Brownian motion on the heat transfer is described. By using the Maxwell velocity distribution relations to calculate the most possible velocity of fluid molecules at certain temperature gradient location around the nano-particle, the interaction between fluid molecules and one single nano-particle is analyzed and calculated. Based on this, a syntonic system is proposed and the coupled effect that Brownian motion of nano-particles has on fluid molecules is simulated. This is used to formulate a reasonable analytic method, facilitating laboratory study. The results provide the essential features of the heat transfer process, contributed by micro-convection to be considered.

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