Numerical evaluation of the scale problem on the wind flow of a windbreak

Liu, Benli; Qu, Jianjun; Zhang, Weimin; Tan, Lihai; Gao, Yanhong

doi:10.1038/srep06619

Cited by 26 publications

(17 citation statements)

References 29 publications

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“…Martin and Kok [77] noted that results reported in past wind tunnel studies observing grain speeds [95] and saltation heights [96,97] were likely impacted by using erodible sand beds of insufficient length in the wind tunnels [98,99]. Liu et al [100] used CFD to confirm that several flow characteristics near obstacles (e.g., windbreak fences) cannot be captured in a reduced-scale wind tunnel or numerical models and thus, results should not be extrapolated directly to natural landscapes. Sherman and Farrell [59] and Farrell [101] formalized an approach to partly test these scaling differences by evaluating two fundamental interactions between wind and sand: the apparent enhancement of the boundary roughness length associated with the presence of a saltation layer and the vertical distribution of mass flux.…”

Section: Discussionmentioning

confidence: 99%

Aeolian Ripple Migration and Associated Creep Transport Rates

et al. 2019

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Wind-formed ripples are distinctive features of many sandy aeolian environments, and their development and migration are basic responses to sand transport via saltation. Using data from the literature and from original field experiments, we presented empirical models linking dimensionless migration rates, urgd (ur is the ripple migration speed, g is the gravity acceleration, and d is the grain diameter) with dimensionless shear velocity, u*/u*t (u* is shear velocity and u*t is fluid threshold shear velocity). Data from previous studies provided 34 usable cases from four wind tunnel experiments and 93 cases from two field experiments. Original data comprising 68 cases were obtained from sites in Ceará, Brazil (26) and California, USA (42), using combinations of sonic anemometry, sand traps, photogrammetry, and laser distance sensors and particle counters. The results supported earlier findings of distinctively different relationships between urgd and u*/u*t for wind tunnel and field data. With our data, we could also estimate the contribution of creep transport associated with ripple migration to total transport rates. We calculated ripple-creep transport for 1 ≤ u*/u*t ≤ 2.5 and found that this accounted for about 3.6% (standard deviation = 2.3%) of total transport.

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Section: Discussionmentioning

confidence: 99%

Aeolian Ripple Migration and Associated Creep Transport Rates

et al. 2019

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“…Dong et al [13] investigated velocity particles near the surface in a wind tunnel and showed that the probability density function of sand particles' lift-off, incident velocities, and their vertical components were a function of sand particles and wind velocity. Liu et al [14] performed a numerical research comparison by computational fluid dynamic (CFD) with an actual-sized experimental model fence, and they realized some flow characteristics near the fence cannot be captured in the reduced-scale experimental or numerical model. Lima et al [15] found that the optimal fence height was around 50 cm, and using a fence with a height more than 1.25 m did not have reasonable economic benefits.…”

Section: Creep Saltation Suspensionmentioning

confidence: 99%

Development of the New Analytic Model for Sand Deposition Particles Downstream of a Fence

Razi

2020

Inventions

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Movement of sand particles is a complicated phenomenon that occurs in nature. In this paper, the main goal is to provide an analytic model for the deposition profile of sand particles downstream of a fence. The analytic model was derived with respect to governing equations and shear flows for upstream and downstream regions. In this approach, we obtain a new expression for the downstream velocity of the fence, which allows for the determination of potential areas of deposition particles by assuming a log-normal distribution profile. A discrete-phase flow (DPM) was used to inject particles in the simulation domain. The DPM gives capabilities to capture spatiotemporal velocities components, as we can define the probability of deposition particles in the downstream of the fence. The proposed model was validated with a numerical model and experimental results. The comparison with field data and numerical results shows that the deposition profile is in acceptable agreement. With some assumptions and modifications about the properties of particles, the results of this research can be extended to snow accumulation downstream of a fence.

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“…While most of the previous investigations (Baltaxe, 1967;Wilson, 1987;Lee and Kim, 1999;Lee et al, 2002;Wu et al, 2013;Dong et al, 2006;Telenta et al, 2014;Zhang et al, 2015;Tsukahara et al, 2012;Savage, 1963;Nordstrom et al, 2012;Telenta et al, 2014;Hatanaka and Hotta, 1997;Alhajraf, 2004;Wilson, 2004;Bouvet et al, 2006;Santiago et al, 2007;Liu et al, 2014;Bitog et al, 2009) focused on the flow characteristics over a single fence, it has been shown by means of wind-tunnel experiments (Guan et al, 2009), as well as…”

Section: Introductionmentioning

confidence: 99%