Aeolian Processes in the Environmental Wind Tunnel and in the Atmosphere

1986 ◽  
pp. 318-321
Author(s):  
J. D. Iversen
Keyword(s):  
Wind Tunnel ◽  
Aeolian Processes

Aeolian processes over gravel beds: Field wind tunnel simulation and its application atop the Mogao Grottoes, China

2014 ◽  
Vol 15 ◽  
pp. 335-344 ◽  
Author(s):  
Weimin Zhang ◽  
Lihai Tan ◽  
Guobin Zhang ◽  
Fei Qiu ◽  
Hongtao Zhan
Keyword(s):  
Wind Tunnel ◽  
Aeolian Processes ◽  
Gravel Beds ◽  
Wind Tunnel Simulation ◽  
Mogao Grottoes

The SANDEE campaign: Electrical effects during sand transport by aeolian processes in the Negev desert and implications for Mars

2020 ◽  
Author(s):  
Itzhak Katra ◽  
Yoav Yair
Keyword(s):  
Wind Tunnel ◽  
Electric Field ◽  
Field Experiments ◽  
Negev Desert ◽  
Energy Output ◽  
Dust Particles ◽  
Sand Transport ◽  
Solar Panels ◽  
Aeolian Processes ◽  
Airborne Dust

<p>The electrification of mineral sand/dust particles during aeolian processes is a well-documented phenomenon both in natural settings and in laboratory experiments. When in motion, small airborne dust particles collide with other suspended particles or impact the surface through the kinetic energy they acquire from the ambient wind. Field experiments will be conducted in conjunction with the AMEDEE-2020 Analog Mars Mission, planned for November 2020 in the Ramon Crater in southern Israel and led by the Austrian Space Forum. During SANDEE, we will deploy a portable wind-tunnel (Katra et al., 2016) at the site, and record particle movements in conditions that simulate sand storms of varying speeds. We will use local Negev desert, as well as Mars-simulant, soil samples that will be placed inside the wind-tunnel. We will measure particles' dynamic, mineralogical and electrical characteristics as they are blown by wind inside the tunnel.  A JCI 114 portable electric field detector will be used to to measure the amplification of the ambient electric field during sand movement. A vertical array of traps oriented along the wind direction will be used for sampling particles, in order to calculate the related sand fluxes and to analyze particle characteristics. The experiment will be repeated at night under dark conditions, in order to observe if light is emitted from electrified dust, due to corona discharges.</p><p>We expect that SANDEE will help decipher wind-speed/aerosol/electrical charge relationships. These have practical implications for future Mars landers, because airborne sand particles are likely to interfere with communications and also to impede the energy output of solar panels due to the electrical adhesion of charged aerosol.</p>

scholarly journals Wind tunnel studies of Martian aeolian processes

1974 ◽  
Vol 341 (1626) ◽  
pp. 331-360 ◽  
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Reverse Flow ◽  
Flow Direction ◽  
High Surface ◽  
Geostrophic Wind ◽  
Horseshoe Vortex ◽  
Distinct Pattern ◽  
Dust Storms ◽  
Aeolian Processes

In order to determine the nature of Martian aeolian processes, an investigation is in progress which involves wind tunnel simulations, geologic field studies, theoretical model studies, and analyses of Mariner 9 imagery; this report presents the preliminary results. Threshold speed experiments were conducted for particles ranging in relative density from 1.3 to 11.35 and diameter from 10.2 to 1290 μ m to verify and better define Bagnold’s (1941) expression for grain movement, particularly for low particle Reynolds numbers and to study the effects of aerodynamic lift and surface roughness. Wind tunnel simulations were conducted to determine the flow field over raised rim craters and associated zones of deposition and erosion. A horseshoe vortex forms around the crater, resulting in two axial velocity maxima in the lee of the crater which cause a zone of preferential erosion in the wake of the crater. Reverse flow direction occurs on the floor of the crater. The result is a distinct pattern of erosion and deposition which is similar to some Martian craters and which indicates that some dark zones around Martian craters are erosional and some light zones are depositional. Analyses of the erosional and depositional zones associated with a 6 m raised rim crater on an open field and a 1.2 km natural impact crater tentatively confirm the wind tunnel results. Application of the wind tunnel results to Mars indicates that for flat surfaces, free stream winds in excess of 400 km/h are required for grain movement. However, lower velocities would be required in regions of high surface roughness, e. g. cratered terrain, and it is proposed that such regions could be zones of origin for some Martian dust storms. Analysis of the Coriolis effect on surface stress shows that surface streaks would be deflected about 15° from the geostrophic wind direction at mid-latitudes.

scholarly journals Aeolian processes and their effect on sandy desertification of the Qinghai–Tibet Plateau: A wind tunnel experiment

2016 ◽  
Vol 158 ◽  
pp. 67-75 ◽  
Author(s):  
Xunming Wang ◽  
Lili Lang ◽  
Ping Yan ◽  
Guangtao Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Experiment ◽  
Tibet Plateau ◽  
Sandy Desertification ◽  
Aeolian Processes ◽  
Qinghai Tibet Plateau

Desert dune processes and dynamics

2001 ◽  
Vol 25 (1) ◽  
pp. 53-79 ◽  
Author(s):  
Giles F.S. Wiggs
Keyword(s):  
Wind Tunnel ◽  
Complex Systems ◽  
Sand Dunes ◽  
Field Research ◽  
Field Studies ◽  
Sand Transport ◽  
Shear Stresses ◽  
Surface Shear ◽  
Aeolian Processes ◽  
Log Linear

This article reviews the advances made and problems encountered in the measurement, modelling and understanding of desert dune dynamics and processes in the last two decades. The main findings of three methods of investigation are reviewed: field studies, wind tunnel studies and mathematical modelling. Whilst major advances in field techniques have allowed an appreciation of the aerodynamic nature of sand dunes, particular problems with field research are evident in the measurement of aeolian processes on dune surfaces. Specifically, it is shown that attempts to ascertain shear stresses on dune windward slopes in the field and relate changes in stress to sand transport rate and erosion/deposition measurements have generally failed. These difficulties have arisen because the non-log-linear nature of wind velocity profiles on dune surfaces as a result of windflow acceleration has made the calculation of surface shear stresses unviable. Significant advances have been achieved in wind tunnel modelling where high-frequency hot-wire anemometer measurements have enabled shear stress and turbulence characteristics to be determined, although problems have been encountered in choosing appropriate scaling parameters. Empirical field and wind tunnel data have allowed the calibration of mathematical models which are now at a stage where the flow field around dunes can be calculated. It is considered, however, that the emerging technique of modelling using complex systems theory may hold the key to constructing a reliable framework for future investigations. New complex systems models have emphasized the need to return to a larger-scale perspective where dunes are not considered as individual elements, but as an integral part of a dunefield where aeolian processes at the dune scale are not thought to be significant.

Sign in / Sign up

Export Citation Format

Share Document