Estimation of some aeolian saltation transport parameters: a re‐analysis of Williams' data

Jensen, Jens Ledet; Sørensen, Michael

doi:10.1111/j.1365-3091.1986.tb00760.x

Cited by 88 publications

(114 citation statements)

References 15 publications

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“…The drag coefficient χ depends on the shape of the grain but also on the Reynolds numbers Re = d |u − v|/ν (ν stands for the air viscosity). At large Re, in the turbulent regime, χ tends towards a constant if the grain is sufficiently rough [27]. In the viscous -Stokes -regime, χ decreases as 1/Re.…”

Section: Motion Of One Grain In the Windmentioning

confidence: 99%

See 1 more Smart Citation

Selection of dune shapes and velocities Part 1: Dynamics of sand, wind and barchans

Andreotti¹,

Claudin

Douady³

2002

The European Physical Journal B - Condensed Matter

273

246

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Abstract. Almost fifty years of investigations of barchan dunes morphology and dynamics is reviewed, with emphasis on the physical understanding of these objects. The characteristics measured on the field (shape, size, velocity) and the physical problems they rise are presented. Then, we review the dynamical mechanisms explaining the formation and the propagation of dunes. In particular a complete and original approach of the sand transport over a flat sand bed is proposed and discussed. We conclude on open problems by outlining future research directions.

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Section: Motion Of One Grain In the Windmentioning

confidence: 99%

“…[25] is that of the saltons while the scaling found by Rasmussen and Iversen [38,39,42] corresponds to the reptons. A third scaling has been obtained by Jensen and Sorensen [26,27] who have used a model to extract the same quantities from experimental measurements of the vertical variation of the transport rate.…”

Section: Equilibrium Transportmentioning

confidence: 99%

Selection of dune shapes and velocities Part 1: Dynamics of sand, wind and barchans

Andreotti¹,

Claudin

Douady³

2002

The European Physical Journal B - Condensed Matter

273

246

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“…The type of data used to represent the dry aggregate size distribution depends on the model used. A model developed by Marticorena and Bergametti (1995) focusing on desert soil mobilization under natural, usually non-crusted, conditions uses threshold friction velocity computations that are dependent on the microped size distributions of erodible soil particles (Sørensen, 1985;Li and Martz, 1994). Chatenet et al (1996) have proposed a sampling and analysis method for determining the dry size distribution of loose microped material.…”

Section: Field Surface Conditionsmentioning

confidence: 99%

Measurement and data analysis methods for field‐scale wind erosion studies and model validation

Zobeck

Sterk

Funk

et al. 2003

Earth Surf Processes Landf

178

107

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Accurate and reliable methods of measuring windblown sediment are needed to confirm, validate, and improve erosion models, assess the intensity of aeolian processes and related damage, determine the source of pollutants, and for other applications. This paper outlines important principles to consider in conducting field-scale wind erosion studies and proposes strategies of field data collection for use in model validation and development. Detailed discussions include consideration of field characteristics, sediment sampling, and meteorological stations. The field shape used in field-scale wind erosion research is generally a matter of preference and in many studies may not have practical significance. Maintaining a clear nonerodible boundary is necessary to accurately determine erosion fetch distance. A field length of about 300 m may be needed in many situations to approach transport capacity for saltation flux in bare agricultural fields. Field surface conditions affect the wind profile and other processes such as sediment emission, transport, and deposition and soil erodibility. Knowledge of the temporal variation in surface conditions is necessary to understand aeolian processes. Temporal soil properties that impact aeolian processes include surface roughness, dry aggregate size distribution, dry aggregate stability, and crust characteristics. Use of a portable 2 tall anemometer tower should be considered to quantify variability of friction velocity and aerodynamic roughness caused by surface conditions in field-scale studies. The types of samplers used for sampling aeolian sediment will vary depending upon the type of sediment to be measured. The Big Spring Number Eight (BSNE) and Modified Wilson and Cooke (MWAC) samplers appear to be the most popular for field studies of saltation. Suspension flux may be measured with commercially available instruments after modifications are made to ensure isokinetic conditions at high wind speeds. Meteorological measurements should include wind speed and direction, air temperature, solar radiation, relative humidity, rain amount, soil temperature and moisture. Careful consideration of the climatic, sediment, and soil surface characteristics observed in future field-scale wind erosion studies will ensure maximum use of the data collected.

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“…This erodibility mainly depends on the soil particle size and the surface properties (Williams, 1964;Gillette, 1974Gillette, , 1979Gillette and Stockton, 1989;Sörensen, 1985;Leys and Raupach, 1991;Shao et al, 1993).…”

Section: Parameterization Of the Horizontal Fluxmentioning

confidence: 99%

Wind tunnel experiments on the effects of tillage ridge features on wind erosion horizontal fluxes

2005

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Abstract. In addition to the well-known soil factors which control wind erosion on flat, unridged surfaces, two specific processes affect the susceptibility of tillage ridged surfaces to wind erosion: ridge-induced roughness and ridge-trapping efficiency.In order to parameterize horizontal soil fluxes produced by wind over tillage ridges, eight-ridge configurations composed of sandy soil and exhibiting ridge heights to ridge spacing (RH/RS) ratios ranging from 0.18 to 0.38 were experimented in a wind tunnel. These experiments are used to develop a parameterization of the horizontal fluxes over tillage ridged surfaces based only on the geometric characteristics of the ridges. Indeed, the key parameters controlling the horizontal flux, namely the friction velocity, threshold friction velocity and the adjustment coefficient, are derived through specific expressions, from ridge heights (RH) and ridge spacing (RS). This parameterization was evaluated by comparing the results of the simulations to an additional experimental data set and to the data set obtained by Hagen and Armbrust (1992). In both cases, predicted and measured values are found to be in a satisfying agreement.This parameterization was used to evaluate the efficiency of ridges in reducing wind erosion. The results show that ridged surfaces, when compared to a loose, unridged soil surface, lead to an important reduction in the horizontal fluxes (exceeding 60%). Moreover, the effect of ridges in trapping particles contributes for more than 90% in the flux reduction while the ridge roughness effect is weak and decreases when the wind velocity increases.

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Estimation of some aeolian saltation transport parameters: a re‐analysis of Williams' data

Cited by 88 publications

References 15 publications

Selection of dune shapes and velocities Part 1: Dynamics of sand, wind and barchans

Selection of dune shapes and velocities Part 1: Dynamics of sand, wind and barchans

Measurement and data analysis methods for field‐scale wind erosion studies and model validation

Wind tunnel experiments on the effects of tillage ridge features on wind erosion horizontal fluxes

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