Profils de concentration de la neige soufflée. Théorie, résolution numérique et validation expérimentale in situ

Naaim-Bouvet, Florence; Naaïm, Mohamed; Martínez, Hugo Alejandro Alvarado

doi:10.1051/lhb/1996052

Cited by 9 publications

(7 citation statements)

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“…In our case, the value of σ s U F was estimated based on the experimental dataset published by Mellor and Fellers (1986), which consisted of 1200 usable data from Mellor and Radok (1960) and Budd and others (1966) obtained by anemometers and aerodynamic snow collectors mounted in pairs on vertical masts in Antarctica. Velocity and concentration profiles were used to calculate the exponent of Equation (4) (Naaim-Bouvet and others, 1996; Fig. 2):…”

Section: Context Of the Studymentioning

confidence: 99%

Back analysis of drifting-snow measurements over an instrumented mountainous site

Naaim-Bouvet¹,

Bellot²,

Naaïm³

2010

Ann. Glaciol.

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ABSTRACT. The NEMO numerical model of drifting snow, whose general outlines are presented in this paper, is based on a physical model for saltation and turbulent diffusion. The model needs a set of input parameters including fall velocity, threshold shear velocity, shear velocity, mass concentration and roughness, which are obtained from empirical formulae and wind speed measured at a given height. To better determine the required field data in an alpine context, our experimental site, Col du Lac Blanc (2700 m a.s.l.), French Alps, was first equipped with one anemometer and blowing-snow acoustic sensors, which proved not to be accurate enough for research purposes in the current state of development even though a new calibration curve was used. We therefore set up a Snow Particle Counter and we returned to the traditional, robust mechanical traps and a 10 m mast with six anemometers, two temperature sensors and a depth sensor to better determine friction velocity and aerodynamic roughness. Based on the studied drifting-snow events we conclude: (1) the proportionality of the aerodynamic roughness to the square of the friction velocity was confirmed, but with a varying proportionality ratio depending on the snowdrift event; (2) values of s U F were relatively well approximated by empirical formulae from data originating from Antarctica, and (3) snowdrift concentration profiles obtained by Pomeroy's semi-empirical formulae for the saltation layer coupled with a theoretical approach for the diffusion layer overestimated the concentration profiles for the studied blowing-snow event.

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Section: Context Of the Studymentioning

confidence: 99%

Back analysis of drifting-snow measurements over an instrumented mountainous site

Naaim-Bouvet¹,

Bellot²,

Naaïm³

2010

Ann. Glaciol.

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“…The three different gauges are compared and the rate of trapping efficiency is suggested from a comparison of the field data with estimated mass-flux data deduced from empirical formulae (Mellor and Fellers, 1986; Naaim-Bouvet and others, 1996). The mass-flux values obtained at the experimental site are lower than the estimated values.…”

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confidence: 99%

Experimental mass-flux measurements: a comparison of different gauges with estimated theoretical data

1998

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In experimental snowdrifting mass-flux measurements many different instruments have been tested (Takeuchi, CEMAGREE Mases, etc.). Very often the results obtained are a function of the gauge used. However, in order to compare data from different instruments, orders of magnitude have to be similar.Since 1992, snowdrifting has been studied at an experimental plot at La Molina ski resort (eastern Spanish Pyrenees). The alpine site, characterized by a plateau topography, is located at 2250 m.In this paper, different gauges used to measure snowdrifting mass flux at this site are presented: one snow-collector column and two types of snow traps. Snow-collector columns (prismatic boxes) are permanent installations and are used to measure the mass-flux episode. Snow traps (Takeuchi, 1980: modified) are lighter and more mobile, and they are used for short experiments during a wind episode during which mass-flux data are obtained.The three different gauges are compared and the rate of trapping efficiency is suggested from a comparison of the field data with estimated mass-flux data deduced from empirical formulae (Mellor and Fellers, 1986; Naaim-Bouvet and others, 1996). The mass-flux values obtained at the experimental site are lower than the estimated values.

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“…Domestic fans were first supposed to be used, but were then dismissed because the air current obtained was not powerful enough. Then, after prospection, a blower was designed and manufactured (F. Naaim -Bouvet et al 1996). The geometric dimensions and air flow were determined in order to obtain the maximum speed range that corresponds to that found at the study site.…”

Section: Experimental Setup (Flow Channel)mentioning

confidence: 99%

Study of the curative role of “Draas” in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

Sebaa

Belhamra

2018

Archives of Civil Engineering

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Sand drifting on road networks in the region of the Lower Algerian Sahara is one of the main problems for the sector. Machines are repeatedly deployed to overcome this phenomenon. The long experience acquired while dealing with the removal of sand from roads pushed us to focus on obstacles called “Draas”. The purpose of this study is to perform an optimization of these special protective structures called “Draas”, using a reduced physical model. Model tests were performed in flow channel. The principle of modeling the wind transport using a reduced model is to simulate the wind using a liquid stream while respecting the laws of hydraulic and sedimentological similarity. The results obtained are extrapolated to make a normal size prototype.

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Profils de concentration de la neige soufflée. Théorie, résolution numérique et validation expérimentale in situ

Cited by 9 publications

References 0 publications

Back analysis of drifting-snow measurements over an instrumented mountainous site

Back analysis of drifting-snow measurements over an instrumented mountainous site

Experimental mass-flux measurements: a comparison of different gauges with estimated theoretical data

Study of the curative role of “Draas” in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

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