Near‐bed mass flux profiles in aeolian sand transport: high‐resolution measurements in a wind tunnel

Butterfield, Graeme R.

doi:10.1002/(sici)1096-9837(199905)24:5<393::aid-esp996>3.3.co;2-7

Cited by 43 publications

(83 citation statements)

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“…The latter is actually the total reflection of various individual particle trajectories and has been regarded as the basis for checking drifting sand (Shao and Li 1999;Dong et al 2002bDong et al , 2004aShao 2005). During field observations or wind-tunnel experiments, the total sand transport rate is often obtained from the integration of the empirical function fitting sand flux data measured at different heights (Butterfield 1999;Liu and Dong 2004;Liu et al 2006). So the sand flux distribution should be emphasized.…”

Section: Introductionsupporting

confidence: 80%

“…In a blowing sand cloud the majority of particles (over 75%) comprises saltating sand (Bagnold 1941;Butterfield 1999;Dong et al 2004a). The problems related to blown sand are determined not only by the total transport rate, which has been studied in detail (Bagnold 1941;Owen 1964;Shao et al 1993;Shao 2000;Spies et al 2000;Dong et al 2002a;Liu and Dong 2004;Bauer et al 2004;Li et al 2004), but also by the vertical sand mass flux distribution.…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers found that 90% of particles were transported within the 0.3 -0.87 m near-surface layer and 60-80% within the 0.05-0.1 m layer with the average transport height reaching about 0.63 m (Dong et al 2004a,b;Butterfield 1999). An exponential decay of sand mass flux with height is widely believed to exist above a mobile sandy surface, especially at moderate to high wind speeds, with the relative decay rate decreasing but the saltating height increasing with both wind speed and sand grain size (Dong et al 2002b(Dong et al , 2004aButterfield 1999;Ni et al 2002;Liu and Dong 2004;Liu et al 2006;Bullard 2006). But some researchers concluded that sand flux or concentration decreases with height according to a power law (Dong et al 2004b;Butterfield 1999;Bullard 2006;Dong and Qian 2007).…”

Section: Introductionmentioning

confidence: 99%

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Improvement and Application of the Similarity Saltation Model: Wind-Tunnel Experimental Investigation and Numerical Simulation of the Vertical Sand Mass Flux Distribution in the Saltation Layer

Lü

Shen

2008

Boundary-Layer Meteorol

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Based upon comparisons between published experimental data and simulated results on the vertical sand flux distribution in the saltation layer, Shao's similarity saltation model has been greatly improved by correcting the average vertical particle lift-off velocity and using a more suitable universal roughness length. By the improved model, the vertical sand flux profile over the bare, dry and loose uniform sandy surface, which is quite representative of real desert surfaces, can be reproduced very well. Meanwhile, the surface transport rate and the characteristic and average saltation heights have been simulated and analyzed in detail, disclosing their relationships with friction velocity, particle size and roughness length, and the possible underlying mechanisms. Besides, the average particle lift-off velocity and the average mean vertical aerodynamic action upon the ascending particle, which determine the saltation process, are explicitly expressed by parameters involved in the similarity model, and their relationships with friction velocity, particle size and roughness length are also described concisely. The corrected average particle lift-off velocity makes it possible to investigate the characteristic particle trajectory, whose initial velocity equals the average lift-off velocity, so as to estimate the average particle against surface impacting velocity and the average aerodynamic action upon the saltation process.

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Section: Introductionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improvement and Application of the Similarity Saltation Model: Wind-Tunnel Experimental Investigation and Numerical Simulation of the Vertical Sand Mass Flux Distribution in the Saltation Layer

Lü

Shen

2008

Boundary-Layer Meteorol

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“…This is partly because the majority of published models have been derived from theory or experimentally from wind tunnel observations with homogeneous sediment beds (Spies, McEwan and Butterfield, 1995;Butterfield, 1999;Bauer, Houser and Nickling, 2004), without sufficient testing or development in the field. Field testing that has been accomplished (Sarre, 1987;Sherman, 1990;Wiggs, 1992) has shown a great deal of variation between the observed rates and those predicted as a function of u * (Figure 18.22).…”

Section: Prediction and Measurement Of Sediment Fluxmentioning

confidence: 99%

“…The practical difficulties inherent in measuring high-frequency turbulence in sand-laden airflows has resulted in a moderate rate of advance in research. In his wind tunnel experiments, Butterfield (1991Butterfield ( , 1993Butterfield ( , 1999 investigated the impact of temporally varying winds (of the order of seconds) on saltation behaviour. He discovered that mass flux and aerodynamic roughness responded within about 1 second to an acceleration in flow, but that the response was several seconds longer in a decelerating flow due to the momentum of the grains.…”

Section: 9mentioning

confidence: 99%

Sediment Mobilisation by the Wind

Wiggs¹

2011

Arid Zone Geomorphology

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Wind can be a particularly effective medium for sediment movement in drylands where a relatively sparse vegetation cover and thin soils combine to create highly erosive conditions on highly erodible surfaces. There is little evidence to suggest that dryland winds are any stronger than their counterparts in humid regions, but the sparse vegetation cover in deserts allows the winds to contact the surface more effectively, and the lack of root systems and moisture to bind sediment together renders it far more susceptible to erosion (Pye and Tsoar, 1990). The efficiency of dryland winds is underlined by the continuous advance and development of desert dunes in the Earth's sand seas (e.g. Bristow, Duller and Lancaster, 2007

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Aeolian particle flux profiles and transport unsteadiness

Bauer

Davidson‐Arnott

2014

JGR Earth Surface

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Vertical profiles of aeolian sediment flux are commonly modeled as an exponential decay of particle (mass) transport with height above the surface. Data from field and wind-tunnel studies provide empirical support for this parameterization, although a large degree of variation in the precise shape of the vertical flux profile has been reported. This paper explores the potential influence of wind unsteadiness and time-varying intensity of transport on the geometry (slope, curvature) of aeolian particle flux profiles. Field evidence from a complex foredune environment demonstrates that (i) the time series of wind and sediment particle flux are often extremely variable with periods of intense transport (referred to herein as sediment "flurries") separated by periods of weak or no transport; (ii) sediment flurries contribute the majority of transport in a minority of the time; (iii) the structure of a flurry includes a "ramp-up" phase lasting a few seconds, a "core" phase lasting a few seconds to many tens of seconds, and a "ramp-down" phase lasting a few seconds during which the system relaxes to a background, low-intensity transport state; and (iv) conditional averaging of flux profiles for flurry and nonflurry periods reveals differences between the geometry of the mean profiles and hence the transport states that produce them. These results caution against the indiscriminate reliance on regression statistics derived from time-averaged sediment flux profiles, especially those with significant flurry and nonflurry periods, when calibrating or assessing the validity of steady state models of aeolian saltation.

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Near‐bed mass flux profiles in aeolian sand transport: high‐resolution measurements in a wind tunnel

Cited by 43 publications

References 0 publications

Improvement and Application of the Similarity Saltation Model: Wind-Tunnel Experimental Investigation and Numerical Simulation of the Vertical Sand Mass Flux Distribution in the Saltation Layer

Improvement and Application of the Similarity Saltation Model: Wind-Tunnel Experimental Investigation and Numerical Simulation of the Vertical Sand Mass Flux Distribution in the Saltation Layer

Sediment Mobilisation by the Wind

Aeolian particle flux profiles and transport unsteadiness

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