A wind tunnel simulation of the mean velocity fields behind upright porous fences

Dong, Zhibao; Luo, Wenhao; Qian, Guangqiang; Wang, Hongtao

doi:10.1016/j.agrformet.2007.05.009

Cited by 138 publications

(150 citation statements)

References 36 publications

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“…At points 4a and 4b, located at the greatest distance from the wind- break, the u x component was reduced by only 12 %, while the u y component was greater on the leeward side of the mesh. This effect is related to the fact that air velocity increases on passing the windbreak edge (Dong et al, 2007;Guan et al, 2009). This is appreciable in the values of u x at points 5a and 5b, 1 m from the windbreak edge, where the maximum values recorded during the test were attained (Table 3).…”

Section: Airflow Characteristicsmentioning

confidence: 99%

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Sonic anemometry and sediment traps to evaluate the effectiveness of windbreaks in preventing wind erosion

López

Valera

Molina-Aiz

et al. 2017

Sci. agric. (Piracicaba, Braz.)

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The present work analyzes the effectiveness of windbreaks against wind erosion through the study of streamline patterns and turbulent flow by means of sonic anemometry and sediment traps. To this end, windbreaks composed of plastic meshes (7.5 m long and 0.7 m tall) were used. Windbreaks are a good means to reduce wind erosion, as they produce a positive effect on the characteristics of air currents that are related to wind erosion processes. Due to their ease of installation and dismantling, plastic meshes are widely used in areas where they are not required permanently. In our study, the use of a mesh of 13 × 30 threads cm

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Section: Airflow Characteristicsmentioning

confidence: 99%

“…Several synthetic windbreaks with different porosity degrees have been tested in a wind tunnel for their ability to reduce wind velocity (Cornelis and Gabriels, 2005) with the objective to determine their effect against wind erosion (Dong et al, 2007;Wang et al, preventing wind erosion Windbreaks in preventing wind erosion Sci. Agric.…”

Section: Introductionmentioning

confidence: 99%

Sonic anemometry and sediment traps to evaluate the effectiveness of windbreaks in preventing wind erosion

López

Valera

Molina-Aiz

et al. 2017

Sci. agric. (Piracicaba, Braz.)

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“…The reduction effect on wind velocity was measured between adjacent fences up to a height of 0.6 m from the ground, and 0.2 was determined to be the optimal porosity value: ε = 0.2, 0.4, 0.6 (Bitog et al, 2009). Of the parameters used to characterize the turbulence fields (vorticity, turbulence intensity, Reynolds stress, and turbulent kinetic energy), only turbulence intensity was observed to be directly related to fence shelter efficiency regarding sediment transport on the surface; the magnitude of the other parameters near the surface was insignificant (Dong et al, 2007;Dong et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Airflow Structure and Dust Emissions behind Porous Fences Used to Shelter Open Storage Piles

Song

Lin

Cao

et al. 2014

Aerosol Air Qual. Res.

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Porous fences can reduce dust emissions from storage piles in open storage yards, but their sheltering effect depends on the airflow structure around the pile, and the shear stress distribution on each surface. In this study, static flow fields were numerically simulated using the standard k-ε turbulence model; the shear stress characteristics and distribution on the windward side, flat-top surface, and leeward side of a typical prismatic material stack were analyzed. The distribution of the aerodynamic structure of each surface of the storage pile was determined according to the flow field data for fences of the porosities ε = 0, 0.2, 0.3, 0.4, 0.5, and 0.6. The results indicated that at low porosities (ε = 0, 0.2) a recirculating flow appeared in the region between the fence and the pile. The shear force acted downward the windward slope, and the maximum dust emission occurred at two-thirds the height of the windward side, rather than at the top, as in unfenced conditions. Using the porous fence simulated in this study, shear stress on the windward side and the flat-top surface first decreased, then increased with increasing porosity; the lowest porosity values were 0.2 and 0.3, and the shear stress on the prismatic leeside changed little with increasing porosity. The numerical predictions indicated that a fence with porosity between 0.2 and 0.3 is optimal.

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“…Nevertheless, there is little research examining the effectiveness of erosion (deposition) inside the checkerboard, and a small number of studies focus on the simulation analysis on the cell flow field in wind tunnel tests (Bofah and Alhinai 1986;Qiu et al 2004;Huang et al 2013). Thus, enhancing the analysis of a fitting curve's erosion (deposition) features may serve to illustrate the method of protection, thereby extending the service life and achieving the best protective effect of straw checkerboard barriers (Iversen and Rasmussen 1999;Dong et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of erosion and deposition of straw checkerboard barriers in alpine sandy land

Tian

Zhang

et al. 2015

Environ Earth Sci

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The morphology and stability of concave surface of the straw checkerboard barriers are the fundamental guiding principles of exploring the mechanism of erosion and deposition, evaluating effectiveness and life period, and optimizing the physical structures of the sand barriers. Especially, in alpine sandy land, characteristics of erosion (deposition) and capacity for anti-erosion and sand burial of straw checkerboard barriers are significantly different from the arid and semi-arid desert regions. Erosion (deposition) measurements and wind-sand observations for different specifications (1 m 9 1 m, 1.5 m 9 1.5 m and 2 m 9 2 m) and slope positions (toe, middle and top of the windward areas) of wheat straw checkerboard barriers were adopted in the eastern shore of the Qinghai Lake study area. The different sizes of straw checkerboards at different windward areas have distinctly erosive and depositional stability and intensity. Including the checkerboards with 1.5 m 9 1.5 m (medium) size at the middle and top, 1 m 9 1 m (small) size at the top and 2 m 9 2 m (large) size at the toe, all the erosion (deposition) coefficients are between 0.09 and 0.11, while their intensities of accumulation are relatively steady (70-90 kg m −2 ), which are the easiest to form stable concaves, and the heights of the barriers change least. Nevertheless, the concaves with small size at the toe are seriously buried, but eroded in the center of some checkerboards with large size at the top, which lead to a short protective period within 3 years and an unbalance between erosion and deposition. Moreover, the transects of erosion (deposition) dominated by southwesterly and northwesterly winds reflect the different intensities of erosion (deposition) at various orientations. On the transect of the NW-SE orientation, at the dune section, each square in the NW direction is strongly accumulated, and the center-SE azimuth is weakly eroded. Usually, deeper accumulation in the center of transects happen in those checkerboards with smaller size and lower terrain slope, which is mainly caused by an obviously positive correlation between the northwest and southwest wind velocity and the erosive depth, and the same is true with the wind frequency (all correlation coefficients are between 0.85 and 0.95). Taking the characteristics of erosion (deposition), sand protection benefits and costs of all types into account, large size at the toe and medium size at the middle of windward slope are the most practical combinations, while small size is suitable to play an emergency treatment role in some extremely serious hazard areas in alpine sandy land.

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A wind tunnel simulation of the mean velocity fields behind upright porous fences

Cited by 138 publications

References 36 publications

Sonic anemometry and sediment traps to evaluate the effectiveness of windbreaks in preventing wind erosion

Sonic anemometry and sediment traps to evaluate the effectiveness of windbreaks in preventing wind erosion

Numerical Simulation of Airflow Structure and Dust Emissions behind Porous Fences Used to Shelter Open Storage Piles

Characteristics of erosion and deposition of straw checkerboard barriers in alpine sandy land

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